How difficult is it to get Google Analytics set up?

OGLE ANALYTICS: Client has a six year old website. They are in the process of creating a new website from scratch and porting old blog posts over to the new site. Sadly, we don`t have ANY Google Analytics data for them for the last six years! We may hit a delay in getting the new site launched - they are talking to a new developer. Q1: How difficult is it to get Google Analytics set up? Q2: If we have about a month before the new site launches, would it be worth it to get it set up on the old site to get some type of data? Thanks for answering my "Dumb" question!