Completely lost about rooting/installing ROM on my S2!

[Brumboy]

Ok so I've just rooted my Samsung GT-I9100 with Odin and everything seems to be fine.

Now I want to install - SensatioN ROM 4.1 - http://forum.xda-developers.com/showthread.php?t=1194765.

How can I do this safely?

Model Number - Samsung GT-I9100
Android Version - 4.0.3
Kernel Version - 3.0.15-I9100XXLPQ-CL223505 se.infra@SEP-94 #3

I've backed everything up with Kies but I just want to load this ROM properly.

Thanks guys