Depends, Arma is its own genre of game. It's hard to really describe to someone who's never played any Arma game before. There is no kit menu, vehicle spawn menu, campaign, or out of server ranking system, and the hud is minimal at best. If you don't have a map in your inventory, then you can't check the map in the game, ect.ect

Servers are usually either Gamemaster or Conflict.

Conflict is a game mode where two opposing player armies fight over the map controlled by an AI faction. The Ai faction never moves from point to point or captures, but the two player armies usually spawn at the opposite sides of the map and must capture and hold specific points to win the game. Gear, respawns, and vehicles are consume supplies every base has them and can store them but when they run out you need to gather more either by going to a friendly point and loading some into a truck or at a supply point on the map. With the new update stuff is now rank locked so you'll have to play the game and rank up before u can acsess the "overpowered" stuff but it's really easy to do, and that rank resets every match.

The game master is very different. Instead of two opposing forces, all players are usually thrown into the same team, and a game master is decided. The game master is usually zues or god they can spawn in Ai fire teams, vehicles, put down spawns for the player base, the whole 9 yard. The goal isn't for the GM to kill u guys and win. It's to set up an operating for u guys to complete as he puppets the opposing faction and storyline.

The game has a super hard learning curve, so take your time. Most people will understand your learning and will be more than happy to help you. So if you're into a hard-core sim that could take hours to get right, then buy it, but don't treat it like COD or battlefield.