You can get the Ti83 Plus guidebook or manual by going to the Texas Instruments web site. You can get there by clicking here!
Once your at the site click the Download item, Ti83 Plus/ Ti83 Plus silver edition guidebook (English). Next you can login
or, click "continue as guest". I'd would click the "continue as guest". Once you have click "continue as guest" the guide book or user manual will download to you.