Hello, and welcome 
Are you doing vinyl or digital releases? The advice would be vastly different for both. I’m going to assume you are doing digital.
Use Bandcamp to release, and SoundCloud to promote.
It’s a good idea to start as a collective; try and develop an identity and sound for your label.
Really nowadays its all about self PR:
Send out promo’s and hustle people to play your music on their radio show and gigs.
Find some tastemakers (urgh) on SoundCloud, Insta, YT & Spotify who will feature your releases
Post your music here in this thread 
If you want your music on streaming and download sites you will need a DSP. That’s where it gets much more complicated but its worth it to reach a streaming audience
Any questions just shout back, and good luck!