A: See the file INSTALL or the manual.
A: There is a short manual in the doc-directory which is partly a reference manual generated automatically from the Femlisp docstrings. There is a very nice book "Practical Common Lisp" by Peter Seibel which is also available online at <http://www.gigamonkeys.com/book>.
A: Work through the demos to see what is possible. Then look through the section "Getting started" in the manual. With the help of your IDE find out what SOLVE is doing here, then look at how the demos are done. Ask on the mailing list, if you should encounter problems.