It is assumed that LaTeX runs on your computer. Download fca.sty, newdrawline.sty, and fcadoc.tex. Put the three files in the same folder and run LaTeX or pdfLaTeX on fcadoc.tex. This should run without errors, and the resulting file will give you instructions of how to use fca.sty. If LaTeX does not compile fcadoc.tex, you need an expert.
With pdfLaTeX the output will be in .pdf format, and can be displayed with kpdf or the Adobe Reader.
As the result of running LaTeX on your .tex-file, you get a .dvi-file. Note that fcadoc.tex uses some special effects that most .dvi-viewers cannot handle (like colour, rotated text, and white fill). To get a better impression of your results, use dvips to translate your file to a .ps-file. Afterwards, you may use ps2pdf to obtain a .pdf-file.
If you use fca.sty more often, you should put it somewhere where LaTeX finds it.