You do the warm ups for the squat, and then the work sets for the squat. Then you warm up for the bench and do the work sets for the bench . Etc. [Notice that you do Squats Bench Deadlift on say Monday, then Squat Press Power Clean on Wednesday, then Squat Bench Dead on Friday, then Squat Press Power clean next Monday, and so on til you are no longer a beginner]
Squatting 3 times a week is doable IF IF IF you remember a few vital things.
First, “Most people don’t eat enough. This means you.” You really have to eat like there’s no tomorrow. Meaning at least a gram of protein every day for every pound of bodyweight, and probably double the calories you are consuming daily now. Sleep of course goes without saying.
Second, you have to get into this gradually. Most people, and we are talking healthy teenagers, use a work set of 80 pounds first workout. Even though they might be able to squat much more. Yes eighty. Not more. Don’t be ashamed to start with much less. Don’t worry, it will be plenty challenging very very soon.
The thing is, you should NOT be doing a “weight I can do 5 reps, but not 6” on your first day. That is way too much. You will burn out almost right away. The body has to acclimate to this new regimen, then find in itself reservoirs of strength to keep going up.
Third, better to be conservative in how much you add. Say Monday you squatted 80, then Wednesday you do 90. After a short while 10 pounds each workout will be too much, so you add only 5 each workout.
Fourth, you gotta use proper form.
Although it is not rocket science, the more you know the better off you are. If you can afford the book, buy it. If you can’t, read here. The guy who set it up did a great job, better than kethnaab.