So I am using an old exam to prepare for a cumulative one. I crammed for this test very last minute, it was $2$ months ago, and honestly I don't remember where I got the majority of these answers from. Hoping to get specifically a bit of a step by step approach that I can then use to study how to ACTUALLY work through them$/$use to do some practice problems for when similar questions pop up$.$ Any help at all is enormously appreciated!! Thanks so much :) Please ignore anything in pencil$/$not printed in the question itself obviously.

I specifically was hoping for an explanation$/$example of how to do the Bonus here, but the bonus requires you be able to see the schematics for $3$ and $4.$ if you're willing to include them too I$\text{'}$d be super grateful, but obviously I totally understand if you'd rather just do the one bonus problem. Thanks so much for your time!