Don't feel you need to do all 4 assistance exercises your first time out. Id start with one and slowly add another in every few weeks until you learn how well you recover. Most people start out in the gym way too hard and burn out within a month or two. Understand that the first 4-16 weeks will be exciting with quick progression and then you'll hit a wall. Most people are mentally unprepared for that wall, get frustrated and quit... But, if you stay the course and follow 5/3/1s principles you'll continue to make slow, steady progress.
For dips, pretty much any triceps exercise... Triceps extensions, push downs, push-ups, close grip bench press, etc.