Most of those screens pop out by pushing the frame up or to one side and then swinging the opposite side out. Then you ought to be able to stretch the screen fabric and reset the gasket (spline). Though you can use a screw driver to push the gasket back in, a spline tool works better. It has a roller with a groove that makes the job easier and less likely to puncture or tear the fabric.
Once you get the track clean, you will not need any lubrication. It would just collect dirt anyway.
To answer your question about which forum to use for your questions, return to the main forum page. There you will see that there are various forums for various questions. You originally posted to the forum for people that own Alpine Coaches, made by Western RV. Your post would better in the General Discussion forum (to where a moderator moved it). Based on your number of postings (showing some experience here), I suspect that like several other Alfa owners, you may have thought that Alpines were related to Alfas.
2003 Alpine 40FDTS (400HP)
Long Beach, CA