There are different methods for doing this. You can cut out all 2048 words, jumble them in a hat, and pull words out one at a time.
Or you can flip a coin 128 or 256 times and convert those flips into seed words (there’s a 1-to-1 mapping between 11 coin flips and a BIP-39 seed word).
Personally, I prefer to deal words using a regular pack of playing cards. I developed a system for this. All you have to do is print out the lookup table, then shuffle and deal two cards. Each two-card tuple yields one seed word.
For example, drawing the eight of spades then nine of diamonds yields “celery”.
