I have been thinking about your question a lot and kept saying I'd wait till I was at my computer and type out something good and thoughtful. But apparently that's not happening so you're getting whatever I type next at 1am and hopefully it's helpful :P

I don't think I can really give advice because it depends on what you want to do, the size of your organisation, and (most importantly) what you and your friends / colleagues want. What I'll do instead is talk about the things I like and dislike at my place and hopefully you can pull something useful from it.

One of the great strengths of anarchism is how flexible it is. I mean this in two ways - firstly, it can be applied in many different forms in many different contexts. The main strength though is that you can more easily change how you work day to day. No single person should be irreplaceable. Of course, everyone has their own strengths, skills and knowledge and you should respect and cherish everyone you work alongside. But there's no one big boss who needs to be there for anything to get done. Everyone is important; no-one is vital. Where I work, it's easy for me to take a day off and know that the work will still get done.

I volunteer for an environmental nonprofit. I'm one of about 70 volunteers and we have 6 staff members, half of whom are part time. There does tend to be a bit of a hierarchy with staff members being viewed as more important. It's something we all try to avoid but because they are paid to be there, they have a lot more available time and effort than those of us who have other things going on in our lives. However, I'm very grateful for the staff because they can take care of all the 'boring but necessary' work - things like applying for grants, paperwork for new volunteers, taking care of rent and utilities, etc. It's useful to have people who are contractually obligated to take care of these things so that I can go about the more interesting (to me) jobs. So my first advice would be to make sure you have any strict obligations covered by someone who is invested in your project.

We have meetings once a month where everyone is invited where we tend to discuss the big-picture issues. This could be topics like "what is our vision" or applying for an award or talking about ongoing problems we might be having. We have an agenda and take minutes, and we have a newsletter and several group chats so everyone can be informed. Communication is very important. However, don't be disappointed if not many people show. We only have about 10% of our people show up any given month. Most people only have an hour or two a week to volunteer and don't care for flat structure, big picture, whatever. They just want to help out and have other things going on. That's fine, because the door is always open for those who do want to have a voice.

I'm not sure if this is a good thing or a bad thing, but I would say expect a lot of informal chats and decision making to end up being important. A lot of issues can be solved just by talking to your teammates, because everyone has the power to discuss and make changes. This is a good strength of flat structure! However, it can mean that sometimes you have an informal chat while working, it doesn't stay in your mind, and one person walks away thinking the problem will be solved and the other person has completely forgotten about it. That might just be because we are always feeling overworked though!

Last thing I'll say just because I feel like this is very long - you have to appreciate everyone's efforts and meet them where they're coming from. Everyone is unique and brings something important with them, and it's important to tell them you appreciate them. If they give an hour a week, they helped and are valid. If they are joining different teams, weighing in, stepping forward, that's great too. You have to make sure that people have the option to take leadership positions but also have the option to step back.

The place I work has really changed me for the better. It's a journey I was already on, but my time with these wonderful people has made me more patient, understand, emotionally open, happy, able to share in the success we make together. Finding the right group of people and letting them be free to make their community better is the essence of anarchism to me