Well any free gear is better than no gear, eh?
Stuff to be aware of about those pouches includes:
as Hibernator says, they are what people usually refer to as "M4 Pouches", although actually they are made to carry STANAG mags, the standardised NATO 5.56mm magazine, so apart from the US M4/M16, they also fit in the British SA80, or L85A2, and a few other guns you'll no doubt soon become acquainted with if you're not already.
You can stuff G36 mags into those pouches, but they won't come back out again so easily - they have lugs on their sides to connect them together and a wide lip towards the top. It's worth noting that one of the main things which slows down mag changes is what to do with the empty - a lot of people use 'dump pouches' for this reason, but whatever you choose, nobody could stuff empty G36 mags back into those pouches using both hands quickly and, in fact, due to their bungies, putting any mags in 1 handed and quickly would be a challenge.
You can fit AK74 mags in them as easily as STANAG mags, but not AK47 at all. Steyr AUG mags should also fit and maybe FAMAS, but nothing for NATO 7.62mm or 9mm SMG's / machine pistols.
They are Coyote Brown, which exact name may not seem like an important detail, but I draw your attention to it simply because it's not the same shade as tan. Personally I would play a few times before you buy anything other than boots and possibly mesh eye protection, but if you are determined to get your own tactical gear before you have any idea what sort of role you will fulfil, what style of play suits you, and thus what equipment you will need to carry and where on your bady (

), then bear in mind that Coyote Brown is not as ubiquitous as tan.
That all said, if you are going to be another M4 toting Strike Back-alike, 3 more of them on the front of your vest will see you sorted.
Something you should get is a good pair of boots. Preferably waterproof, but definitely with good ankle support. The debate will doubtless always rage over mesh or lens eye pro, but the plain facts of the matter are that nobody has ever lost their sight as a result of a BB penetrating mesh and lenses do fog, even though you can put stuff on them to reduce it. If your local site uses lensed goggles or paintball type full face masks with polycarbonate eye shields for rental customers, I would get yourself some mesh instead.