2
its simple
1.) create a MySQL database and user.... be sure to add the user to the database with all priveledges
2.) assuming you have already downloaded the lates copy of XOOPS upload the contents of the html directory to your public_html directory
3.) chmod the cache, uploads, templates_c, and mainfile.php to 777
4.) navigate to your site and do the install
5.) delete the install folder in your public_html and chmod your mainfile.php to 444
6.) Voila!
^^ all from memory, if anything it speaks of how many times i've had to do it to recover from a goof up.