After I download it I unzip it. After you unzip you have to find where Reaper keeps it's FX Chains on your hard drive. For me it's
C
Documents and Settings
Owner
Application Data
Reaper
FX Chains
Once you find it just paste it in there. When you open reaper and want to add it, it will be there. You need to actually have the fx they are using in the FX chain for it to work. They are just giving you the chain presets. If there are 4 fx in the chain and you have 2 tyhey will work but you have to get the other 2 when it goes to look for it. Most of the ones there are free though