Learn to Crochet!
Crochet Gif Tutorials: Puff Stitch
The version of the puff stitch I’ve demonstrated here is a ‘7 loop puff’ (7 loops on your hook before you wrap the yarn over and pull through them all). This is probably the most common type of puff, but there can be a lot of variation between patterns. Sometimes they’ll require a 9 loops or 5 loops for more or less puffiness. Patterns will generally tell you how many loops to do, but if they don’t, I’d say 7 is pretty standard, or pick the puff level you like best.
Also, some patterns count the securing chain as a stitch on its own rather than as part of the puff - check your pattern so you don’t accidentally do it twice!
The trick with the puff stitch is to keep your yarn nice and loose.
Good luck! XX