You will need identification (not sure about passport). Most will also want an imprint of your credit card in case you bring the bike back a ltlle worse for wear. It's a good idea to take clear dated photos of the bike that detail any previous scratches or dents.

The insurance contract is part of the rental agreement. I would advise getting a copy of it, then leave the premises to read it over in detail. Then return to rent if you decide all is well. Otherwise just say "F*&% it" and throw caution to the wind, sign it in complete ignorrance and hope that nothing happens.