The scene is big. You can do the wild.
The scene is not too big. Just do CQB or something like that.
The one I played was about the size of 4 basketball courts. Do melee CQB battles.
Paintball guns about 20 or so. As well as camo uniforms helmets masks. Undershirt gauntlets.
But for some other business place wouldn't be enough. To be bigger,
such as the field extension training that many companies like to engage in nowadays. That would require a place at least the size of a standard soccer field.
And the corresponding extension training equipment. (This can be checked. Relatively specialized)
Since the general real CS site will be more remote, depending on your site, in addition to play. Also provide food and drink, or other rest and recreation sites.
This will require you to plan your own.
Work. There is grounds maintenance, equipment maintenance, medical equipment and related personnel. Coaches. Referees. That's about it.
There are more specific breakdowns. Also not a know can answer the end.