It's very straight forward.
Right now there's 4 perks, each perk generally uses a single type of weapon, so Commando is assault rifles, Support is shotguns, Medics are the medi weapons and berserker are melee weapons, you can use other weapons on other perks, but a commando will have bonus damage etc while using an assault rifle. They also have other benefits, like support can distribute ammo and medic can heal.
There's a certain number of rounds depending on what the server is set up as, 7 rounds is normal, after each round the trader appears, which you can find from the compass at the top of the screen as the wave is occuring, or the arrows which float around your screen after the wave has finished, at the trader you can refill your ammo, buy weapons and buy body armour. You can also pick up weapons around the map to sell them to the trader for extra dosh. With weapons there's a weight limit, so you can only carry a certain amount, so you have to have enough money and weight capacity to get them.
After the last wave there's a boss which you have to kill, so make sure you stock up fully after the final wave has been.
Yes there is.
