BSD my wife and son recently went to do historical research for a university dissertation and offer the following advice and tips:
1. Check on line for the documentation you will need to produce to become a 'member' - passport, utility bill etc.
2. There are copying facilities, but if you propose to copy a lot of pages, take an iPad or iPhone with Scanner Pro installed and take photos which come out as PDFs.
3. It is quite a beaurocratic process; you will need time and patience. It's best to get there early - it can get quite busy which slows the process down.
Good luck.
mcdhu