Make sure you have XOOPS RC 3.1.0 CVS installed.
Upload the unpacked files of Shoops into the directory yoursite/modules/
Install Shoops by pointing your browser to System Admin > Modules
Grant write permissions (chmod 777) to the directories:
your-shoops-folder/cache
your-shoops-folder/images/products and the contents inside
your-shoops-folder/images/vendors and the contents inside
Grant write permissions (chmod 666) to the files:
your-shoops-folder/cache/rates.php
your-shoops-folder/cache/shoops.config.php
Now point your browser to your XOOPS admin page and modify the Shoops Preferences. You must do this before palying around with Shoops.