What this achievement description is saying is you need to make the same word three different times in the same game. The easiest word to do this with is aa (according to the snap attack dictionary it's a word) for many reasons. First of all it is made up of vowels, so you're likely to have it on the board and in your rack. Second of all, you only need two a's to appear on the board, vs. 3 to appear on the board. Lastly it's two letters.
So if you do this with aa then you need to play in a game where there is at least 2 a's somewhere on the board and at least one a in your rack. Then place your a in your rack next to one of the a's on the board. If the word "Quake" was on the board, it would look like this
Then, place your a on the other side like this
Then go to your second word that has an a in it. Suppose this word was "Steals". It would look like this
Hopefully I didn't make that too confusing.
Comment with problems or anything else (feedback etc.)
Also make sure to upvote please.
Thank you. Happy hunting.