It's a bit of fun.
You have six attempts to guess a five-letter word in a way similar to the Mastermind game of decades ago. With each guess your letters turn one of three colors - black means the letter isn't in the word at all, yellow means it's there but in a different position and green means it's in the right place.
To give you an example, if the word is DRIPS and your guess was SLOPE the S would show yellow, the P would show green and LOE would turn black. You'd know the target word had an S in it but not in the first position, and that it had a P in the fourth position.
There are lots of different strategies to approach it. Personally I start with words that have lots of different vowels so I can get a handle on which vowels are present, while also getting as much useful information about other common letters as I can. So I might start with PIOUS or QUIET or similar and go from there.
Sometimes you end up with a rush to guess the one last letter before you run out of attempts. I forget what the final word was I hit on my sixth attempt, where the last four attempts had four correct letters and it was just a question of guessing which of the possible options the final letter might have been. At that point it's purely down to luck.
