Extract the apps and ctgpr folders to the root of your SD card.
It is important to note that the official developers, Chadsoft , do not distribute CTGP-R as a pre-built WBFS or ISO file. This is largely due to legal reasons and their commitment to "anti-piracy" measures—the mod traditionally requires an original Mario Kart Wii disc to run on a console. ctgp revolution v103 wbfs updated