How can I share my wireless router?

Hello, I’ve bought a SITECOM Wireless Router 300N Limited Edition in the summer 2009 last year, I can use it, shared it with other users. But now my problem is that I forgot how to add users to my router and secure it because I realy need to add someboddy. I shared it with my PS3, my ipod touch my sister’s laptop and mine. So please help me to add users.