When you say "Jesus wanted them to understand about the Father, Himself (Son) and Holy Ghost and their relation to each other and to the disciples." I have to ask:
What is Your understanding of this? ...
My position is the OP linked materials position, as standing upon the scriptures therein provided, for any to consider as well (Pro. 18;13,17). My understanding, is standing under the Bible (Isa. 8:20; 1 Pet. 4:11) as final authority in all matters of faith and practice. I do not adhere to "private interpretation" (2 Pet. 1:20) of the scripture, and am forbidden to do so, since it is the Author of scripture, which interprets the scripture (Gen. 40:8), and given in such a fashion that the words of God explain themselves, perfectly (Jhn. 10:35), and are internally defined, "line upon line" (Isa. 28:10,13). I (and any really) am only allowed to 'amen' ('second') the scriptures, in what they say (Isa. 8:20; 1 Pet. 4:11).
There is a chapter on each; speaking of the Father
(Chapter's 3-4), the Son (Jesus;
Chapters 5-7) and the Holy Ghost / Spirit
(Chapters 8-9) in the provided and linked material. Here is a small excerpt on each
[pages 121-123, edited]:
"... [Page 121] QUESTION: WHO MADE THE WORLD, THE HEAVEN (SKY) & EARTH, AND ALL THAT IS ON IT?
GOD – ELOHIYM (THREE PERSONS/BEINGS THAT WORK TOGETHER IN HARMONY, AS FAMILY, AS MARRIAGE, AS TEAM, AS CHORD)
“Elohiym” (Gen. 1:1 HOT, etc.) x (a lot) (true plural, 3 or greater form), “us” x 4 (plural pronoun), “our” x 3 (plural pronoun): Gen. 1:26, 3:22, 11:7; Isa. 6:8; “we” x 3 (plural pronoun): Jhn. 3:11; “Creators” x 1 (Ecc. 12:1 HOT, “בוראיך”) (plural pronoun) (see also Job 33:4; Isa. 43:7; Rom. 11:36; 1 Cor. 8:6; Heb. 1:2, 2:10; Rev. 4:11), “Makers” x 3 (Job 35:10 HOT, “עשׂי”) & (Psa. 149:2 HOT, “בעשׂיו”) & (Isa. 54:5 HOT, “עשׂיך”) (plural pronoun); “Holy Ones” x 1 (Pro. 9:10 HOT, “קדשׁים”) (plural pronoun); &c; Verbs are plural in association with Elohiym: Gen. 20:13, “התעו” (wander) connected to Elohiym is plural; Gen. 35:7, “נגלו” (revealed) connected to Elohiym is plural; Deu. 4:7, “קרבים” (nigh) connected to Elohiym is plural; Jos. 24:19, “קדשׁים” (Holy) connected to Elohiym is plural; 2 Sam. 7:23, “הלכו” (went) connected to Elohiym is plural; Psa. 58:11, “שׁפטים” (judge) connected to Elohiym is plural; Pro. 30:3-4, “קדשׁים” (holy) connected to vs 4 with the “name” (of the Father), and that of “son’s name”. Even the word “Adonai” (“לאדני”) is given mostly / majority in the plural (Gen. 18:30; Exo. 34:23; Deu. 10:17; Jos. 3:11,13; Psa. 45:11; 114:7; 135:5; Mal. 1:6).
(A.) Genesis 1:1 KJB - In the beginning God (H430; Elohiym, true plural, 3) created the heaven and the earth. (“God said”, “God made”, “God saw”)
(B.) Zechariah 3:2 KJB - And the LORD said unto Satan, The LORD rebuke thee, O Satan; even the LORD that hath chosen Jerusalem rebuke thee: is not this a brand plucked out of the fire?
(C.) 1 John 5:7 KJB - For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one. (“agree in one”, parallel in 1 Jhn 5:8 KJB)
(D.) Ecclesiastes 4:12 KJB - "... a threefold cord is not quickly broken." [Page 121-122]
(1.) The Person / Being of the Father (Mat. 6:9; Luk. 11:2 KJB), JEHOVAH (“the LORD”, Gen. 19:24b; Zec. 3:2b KJB), the “Ancient of Days” (Dan. 7:9,13,22 KJB), “the only true God” (Jhn. 17:3 KJB; “τον μονον αληθινον θεον”), “God” (Psa. 45:7b.; Heb. 1:9b.; Jhn. 1:1b KJB, “τον θεον”), speaking to the Son:
(A.) Revelation 4:11 KJB - Thou art worthy, O Lord, to receive glory and honour and power: for thou hast created all things, and for thy pleasure they are and were created.
(B.) Revelation 10:6 KJB - And sware by him that liveth for ever and ever, who created heaven, and the things that therein are, and the earth, and the things that therein are, and the sea, and the things which are therein, that there should be time no longer:
(C). Genesis 1:6 KJB - "And God said, ..."
(2.) The Person / Being of the Son, Jesus JEHOVAH ((H3444; H3068) “ישׁועתה ליהוה”; Gen. 49:18; Exo. 14:13; 2 Chr. 20:17; Jon. 2:10; Psa. 119:174 HOT) or JEHOVAH Immanuel ((Psa. 46:7,11) Psa. 46:8,12 HOT, (H3068; H5973; H430), “יהוה ... עמנו... אלהי”), “the LORD” (Gen. 19:24a.; Zec. 3:2a.; Heb. 1:10; Psa. 102:12,25-27; Heb. 13:4-8), “the son of man” (Dan. 7:13), “the only begotten” (Jhn. 1:14,18, 3:16,18; Heb. 11:17; 1 Jhn. 4:9, is basically monogene (μονογενῆ; Jhn. 3:16; Heb. 11:17; 1 Jhn. 4:9) or monogenes (μονογενὴς; Jhn. 1:18) or monogenous (μονογενοῦς; Jhn. 1:14, 3:18)), “the Lord Jesus Christ, the Son of the Father” (2 Jhn. 1:3; Κυρίου Ἰησοῦ Χριστοῦ τοῦ υἱοῦ τοῦ πατρός), “the express image of his (God, The Father’s) person” (Heb. 1:3; χαρακτὴρ τῆς ὑποστάσεως αὐτοῦ), being Himself also “God” (Jhn. 1:1c., “θεος ην ο λογος”; Jhn. 1:14,18, 3:16,18; Heb. 11:17; 1 Jhn. 4:9; Psa. 47:5a.; Heb. 1:8,9a.), even “O God” (Heb. 1:9, “ο θεος”), and the “son of man” (Dan. 7:13), the “fellow” (Zec. 13:7), who acted, “made” all things (Jhn. 1:1-3; Eph. 3:9; Col. 1:16; Heb. 1:1-3), on behalf of the Father’s will (Pro. 8:22-36; Jhn. 5:30, 6:38), though, a father in His own right (Isa. 9:6; Heb. 2:13; Isa. 8:16,18; Jhn. 13:33), and yet also the perfect Son (Num. 19:2; “without spot, wherein is no blemish, and upon which never came yoke”), the “Angel (Messenger)” (Mal. 3:1b) “of the LORD (Father)” (Zec. 3:1); “Michael” (Dan. 10:13,21, 12:1; 1 Thes. 4:16; Jud. 1:9; Rev. 12:7), the great “I am” (Jhn. 8:58; ἐγὼ εἰμί), see also Jhn. 4:26, 6:20,35,41,48,51, 8:12,18,24,28,58, 9:5, 10:7,9,11,14, 11:25, 14:6, 15:1,5, 18:5,6,8, 13:19:
(A.) John 1:1 KJB - In the beginning was the Word, and the Word was with God, and the Word was God.
John 1:2 KJB - The same was in the beginning with God.
John 1:3 KJB - All things were made by him; and without him was not any thing made that was made.
(B.) Ephesians 3:9 KJB - "... God, who created all things by Jesus Christ:"
(C.) Colossians 1:16 KJB - For by him were all things created, that are in heaven, and that are in earth, visible and invisible, whether they be thrones, or dominions, or principalities, or powers: all things were created by him, and for him:
(D.) Hebrews 1:1 KJB - God, who at sundry times and in divers manners spake in time past unto the fathers by the prophets,
Hebrews 1:2 KJB - Hath in these last days spoken unto us by his Son, whom he hath appointed heir of all things, by whom also he made the worlds; [Page 122-123]
(E.) Genesis 1:7 KJB - "And God made ..."
(3.) The Person / Being of the Holy Ghost / Spirit, the “another Comforter” (Jhn. 14:16 KJB), the “Spirit of truth.” (Jhn. 14:17 KJB), “Comforter ... the Holy Ghost” (Jhn. 14:26 KJB), the “LORD” (Zec. 3:2c KJB), and a father in His own right (Mat. 1:18; Luk. 1:35; 1 Pet. 1:23; Jhn. 1:13, 3:3-8; 1 Jhn. 3:9, 4:7, 5:1,4,18 KJB), yet differing than the Father or the Son (Isa. 48:16; Jhn. 14:26 KJB):
(A.) Job 33:4 KJB - The Spirit of God hath made me, and the breath of the Almighty hath given me life.
(B.) Genesis 1:2 KJB - "... the Spirit of God moved upon the face of the waters."
Is this what you were seeking to know about my position?