The Equip Menu
When you earn enough money and have done
your shopping at the store, you would want to try them out.
Be it clothes, shoes, guns, whatever. You can access the Equip
menu through the lobby, in a waiting game room or even through
the store interface.
The button looks like this: 
This
is the what the equipment menu looks like.
The left side shows what you have currently
equipped. You can equip a headgear (not implemented yet), body
armor, gloves and shoes.
Quantity means how much
the item can sell for back at the store. Items do not sell back
for half-prices unfortunately.
Level means what level
you have to be or higher to equip them.
You can equip 1 melee weapon, 2 guns (SMGs,
Pistols, Revolvers, Shotguns, Rifles, Rocketlauncher, Heavey
Machinegun), and 2 items, which are flashbangs, grenades, medical
kits and defense kits.
The bottom two represent accessories,
such as rings that give you extra stats.
To Equip something else, click on the
weapon/clothes in the right side, and drag it to the left to
replace it. In this example, I am replacing my rusty sword with
a rusty dagger.
Here
is an example