Here are a few things to consider. If you want to email me at NPTITim@aol.com, I would be happy to share my guidelines and stuff for my own team.
Why do you have a team?
What do team members get out of being on the team?
What do you (the team founder) get out of hosting the team?
Is there a fee to be on the team and if so how much?
Are you going to compete as a team and if so who will pay for the team entry fee?
Who decides who is on the team and how do you kick people off of the team if necessary?
Is there anything mandatory team members must do (like attend a certain number of meets, practice, meetings, etc)?
Are you focused on a certain type of powerlifting (raw vs geared, drug free or not, bench only, etc). You don’t have to be, it is just useful to know the general direction you want to head and the federation(s) you want to compete in.
Are you going to have a team uniform (T-shirt, singlet, gym bags, whatever) and how will that work? Will you buy it and they buy it from you? They buy it and you order it? Everybody does their own thing, etc.
Does the coach dictate how the team members train or do they get to train however they wish? Same thing for picking meet numbers.
It is an all male team or are women allowed?
I think that is a good starting point. Even though those questions can go in depth this does not have to be a massive time committment on your part, but it could be if you want to control everything personally especially including running each training session.
For me personally most of my team does their own thing when it comes to training, myself and my workout partner always workout at the same time (he is also on the team) and anyone is welcome to join us. I am available for questions and help with programming and meet prep but I don’t dictate what people do unless they ask me. One of my main goals was just on meet day it is great to have a group of 5, 10, or even 20 people routing for you, helping you on the day of the meet taking pics, videos, having dinner afterward, warming up, etc. I had that in college and lost it once I trained in the “real world” so one of my goals in creating a team was to create that atmosphere again, both for myself and for the other members of a team. I have been to meets where I was the only person there (a one man team so to speak) and while you can do it it is not nearly as fun, at least for me.
When it comes to setting up training, you have already gotten some good advice. On heavy stuff you can go up to about 5 people or so but on assistance stuff any more than 3 really drags out, break bigger groups into several smaller groups (3 groups of 2 or something for example). Use the rounds system so start with the weakest lifter and they go first, then the next, etc for 1 set, then repeat. Try to have warm-ups be the same weight whenever possible to save time. It make take some yelling but you can definitely get each person to do their set in 30-60 seconds even with a lot of weight. Know who the spotter is, who the loader is, who the lifter is and kind of set up a rotating system where each person moves to the next station to keep it effecient. If you don’t expect everybody to train at the same time then this will be less of a problem. Also you may want to get an “assistant” coach that helps run the session, or runs another session, or will just help you out. You may find personally that if you are “in charge” of 5-10 lifters, especially newbies, it may be hard to channel your own energy toward your own workout. Definitely try to break up the groups so there are some similar strength people, if you have 15 lifters you could have an A group of 5, a B group of 5, and a C group of 5 (advanced, intermediate, beginners, etc) and then you can assistance groups like A-1, A-2, etc which is just 2 or 3 people so they can go faster. If you have a lot of equipment you can have everybody do the same thing at the same time (like 4 or 5 people doing DB lateral raises at all once). Once you start to get a decent sized group be prepared for people to say they are interested and then skip sessions, not train that hard, have little injuries, and most common of course is to back out of a meet at the last moment. How you will deal with that is up to you but be prepared for it. If you have a lot of beginners you might want to have a few meetings on form (like a squat meeting where you teach everybody how to properly squat) and then something on meet prep so they can know what to expect, how the day will go, etc.
Sorry if this was too long, I was just kind of thinking off the top of my head. Like I said, email me if you want more specific or personal info. Good luck with it,