Just Dance 2022

Every song has at least two Gold Moves in it, and at most four. Gold Moves are typically one-off moves that happen during the song. The entire screen will turn gold to let you know one is coming up. To "perform" the Gold Move, it must say 'Yeah!' on the top of the screen where it normally shows you the rating you got on that dance move. This essentially requires that you get at least a 'Good' rating on that move, in my experience.
 
As with all moves, this game is extremely lenient with what it accepts, so this should be pretty easy to have happen naturally. Since you'll be earning the Megastar rank on all songs for the Dance Legend (100G) achievement, you'll be playing every song in the game at least once, and probably at most five times. During this time, you'll almost unavoidably unlock this achievement, since successfully performing the Gold Moves in a song really bumps up your star rating. Just like with earning the Megastar rating on all songs, practice makes perfect. It shouldn't take more than a playthrough or two of a song to remember the Gold Moves and perform them at least well enough for them to count.