You can find "step by step" instructions here -->
http://www.ubuntugeek.com/how-to-ins...in-ubuntu.html
I googled it.
Not sure why you want OO, instead of Liber Office. Liber is a fork of OO, runs faster, does everything OO does.
You need Java installed before you install either. If you install Liber, Synaptics should look after Java at the same time.