New player

I am an old paintball player who is making the move into airsoft. I look forward to joining you soon. I am buying a G&G Airsoft Combat Machine M4 Raider High-Performance Full Metal Gearbox AEG Rifle w/ Integrated RAS and Crane Stock. Any tips or rules I should be aware of? Mabey even tips on what gun to buy?
I hope that you guys stay active for a long while. How is the turn out? Are M4 magazines universal? Will a magazine made by a different company fit?

I thought M4 mags worked on most guns. I'm new to airsoft though, so I might be wrong.

hey guys most m4 mags can b e used for several different guns,. theres a man whom, i play with who hass an actr and it uses m4 mags. ithey can be used for certain different guns though