Assuming you're starting with the prelude...
I don't have my metronome handy so I can't offer an exact tempo but you could download a midi file to hear an example of how fast it's typically played. Also,
http://www.naxos.com should have it available for you to listen to online. The "tr" means trill. In baroque music, a trill is always started from the note above. For example, if the note with 'tr' above it is a B, you would start the trill on C natural. The trill is usually performed more or less in tempo but with any solo piece you do have a bit of freedom with it. The 'tr' marking only applies to the note that it's assigned to. Are you learning it at written pitch or down an octave? Hope this helped.