Guys i really need some help.

I just bought myself a 4gb SD Card, followed the guide on the Wiki, which somhow installed the old 0.0.8 vesion... How can i easily update it?

On my PC i have in front of my the file gingerbread.tar.bz2

Thats all what steps do i need to do to update it to this.. Obviously copy the file over to the n900 but not sure where it goes or what i do to get it update.

Thnaks heaps