/bind numpad4 "netgraph 1"The core of the whole system. /bind attaches a command to a key; the command goes in quotes. Anything you can type into chat, and every internal engine command, can be bound this way.
VIP players can summon a mailbox anywhere. The engine exposes it as a GenSendMessage action, which means it can be bound like any other command.
/bind m "gensendmessage Vipaction_Mailbox activate"