No need to go to a bank -- you can do the whole thing via the website and USPS. The instructions are here:
https://www.treasurydirect.gov/indiv/research/indepth/smartexchangeinfo.htmIt's a slightly complicated process, but if you follow every step carefully, it's no big deal. The whole thing, from mailing the bonds in to your online account being credited, takes a couple weeks.
Setting up a treasurydirect.gov used to be an experience in and of itself (involving, among other things, them mailing you a
secret decoder ring authentication card). I believe the process has been streamlined a bit (although their logon procedure is still.. unique).
Note that the instructions accompanying the "manifest" you have to print out explicitly state that you
not sign any of the paper bonds. Not sure what happens in this case.