I am doing Step 4 "Setup The Character Blueprint" and I am having issues with Step 11 "Click the Class Defaults defaultsButton.png button and assign the new AI Controller (Follower_AI_CON) to the AIController Class property in the Pawn category."

I don’t know where the Class Default button is and I can find the Pawn Category

With the Blueprint open, the button is in the tools icon row. Alternatively, you can also select your class’ root object (the character itself).

Should you accidentally have closed your toolbar, you can make it show up again in the Window dropdown.

53262-bp_showtoolbar.png

For next time, it would help if you link to the tutorial you’re following in your question.