Hi! Im ikergamers

Hello! Im ikergamers and I discovered this redstone community today. Now, i`m pretty much new to this complex redstone stuff, since the only things with redstone I used to do where house defense system with simple redstone clocks in survival mode :/. Also, I am willing to apply for the school server, but I do not know where to write the /apply command. Would somebody be kind to tell me?

Do /apply in-game on any part of the server.