First, make sure you unzip any Rainlendar skins to the Rainlendar skin folder. If your using the new 2.0 version of Rainlendar then rightclick on the default Rainy thats on your screen ( or rightclick on rainy icon in system tray )click on 'options' then click on the Skin tab at top...highlight the rainy you want, click ok.
The new version of Rainy will work with previous version of rainlendar skins that uses ini notepad config..but the Event list background may not work. You can download the previous version of Rainlendar at the Rainy website and you can run both the new 2.0 and the 0.22.1 version that is more compatible with 90% of the rainy skins at this time.