BW3.5 to BI 7.0

Hi,

My organisation is moving from 3.5 to BI 7.0

My activitiy is focussed primarily on Roles & Authorisation. In this regard what are the steps that that I need to do ? I am at a loss more so as I am not a BW-BI guy ! and I have taken the challenge!

Where Do I begin ? What are the steps ?