Old school mode has weapons and perks scattered throughout the map.These weapons and perks are marked by yellow lights and you can choose to pick them up by pressing F or just use what weapons were given to you at spawn. Also, in old school mode you can sprint without running out of breath and jump higher and farther.
Found out the reason why it wasn't working. The maps were all set to FFA and that's the only gametype Old-School Mode wont work on. I'll change all the maps to TDM right now.