I’m a SUPER beginner and I just can’t land the side mount to do man on the flying trapeze, Eli hops etc. I can land the front mount to bind and stuff, I’ve basically mastered binding. Any suggestions?
Practice, of course. 
There’s no real “side mount” per se. The Man on the Flying Trapeze IS your standard side mount. Do not think about a mount that transitions into the trick. Just try to land Man on the Flying Trapeze and then don’t do any of the old-school swinging stuff that goes after the landing. People will still call this mount “Trapeze”.
A clean breakaway with the yoyo on-axis and which makes a straight line in front of you is a must. Don’t bother with power. Just do a nice moderate throw.
Tutorials show a stationary finger, and I suppose it’s OK to do that for practice (it will show if your throw is straight or not!!) but in reality I don’t think many of us throw a breakaway and keep our non-throwhand (NTH) finger just pointed out.
As the yoyo comes higher than your NTH (ie. starts to swing around your pointer finger), slide it smoothly towards the yoyo. This will help force it to be on the same plane as the string. Stop this “sliding” motion when the finger is at a comfortable distance from the yoyo itself.
“Comfortable distance” is a matter of taste. When I first started, many players and tutorials advised me to try to land the trapeze with the yoyo as close to the finger as possible. Mathmatically, less string length going around the NTH means your chance of landing on the string is higher. However, I found myself too distracted by focusing on this distance, and sometimes I’d be TOO close and touch the yoyo (causing it to stall). For me personally, I tend to land about 1/3 of the way (with the yoyo closer to the NTH).
Once you’re landing consistently, you’re going to find you’re ignoring any and all advice anyhow (except for the clean throw part!) because it’ll be intuitive and any “techniques” like that sliding motion I talked about will just come naturally when needed (or your finger may just stay stationary when not or if you start to develop minimal hand movement as part of your individual style)…
So…
Practice. That’s about it.
wow. Thank you do much!