vanity exercises = accessory exercise (eg. bicept curlz) that don't matter for a beginner. If you get basic compounds lifts and get strong on those, you are on your way to looking good.

I am not condemning bicep curls, but If u can;t perform at least 10 perfect chin ups why bother curling. Same as leg extension, In any real world situation, do u find yourself sitting down, extending your leg and exerting force ? that's why we have the squat. (jumping, getting up from the toilet seat)

basic compound lifts = squats, deadlift, bench press, military press.