Ring Group NOT using @home

HI there. I am very new to asterisk and am wondering how I might set up a ring group. Everything I see tells me to use asterisk@home with amp and I am not using either of these. All I want it for say extension 110 to ring extention 101, 304 and a cell number. how do I set this up? And what happens if one or more of those are busy? will it give me a busy or will it ring the others instead and ignore the busy.

Thank you for your help.

Asterisk 1.2.1