You seem like you are familiar with back-propogation. From my understanding, tokens are basically just a bit of information that is assigned a predicted fitness, and the token with the highest fitness is then used for back-propogation.

Eli5: im making a recipe. At step 1, i decide a base ingredient. At step 2, based off my starting ingredient, i speculate what would go good with that. Step 3 is to implement that ingredient. Step 4 is to start over at step 2. Each "step" here would be a token.

I am also not a professional, but I do do a lot of hobby work that involves coding AI's. As such, if I am incorrect or phrased that poorly, feel free to correct me.