Assistance lifts are important to a). aid in progressing your compounds and b). for improving weak areas, strength-wise and aesthetically. For instance, you want to grow your arms. In addition to the compounds, you should be doing pull-ups, biceps curls, triceps extensions, etc. Take a look at the OP again and pick a program you want to do...then come back and we'll answer any other questions you have.
Your cardio-game seems good! HIIT and sprints are the best way to burn fat quickly.
I do do biceps curls, triceps extensions, and reverse pull-ups, I just didn't know they were called assistance lifts. The quick google search indicated assistance lifts were regular lifts with some form of assistance. Box squat, starting a deadlift a little off the ground via a rack, and so on.
Will do! Thanks for the info. I just wish this side fat would go away. Chest, arms, legs, all muscle and bone. Just that blasted side is holding onto fat like I'm about to hibernate for the winter.