Exporting a MIDI is easy. When you go to "Save As", instead of saving as an ".mus", click ".mid".
Making PDF is a bit trickier. What you're going to need to do is download a PDF creator such as "PrimoPDF" (that's what I use [it's free]). Once installed, in Finale, go to Print and set up the printer as the PDF creator you downloaded, then print. It should send the Finale score to the PDF creator and make a PDF of the score.