First make sure you're downloading the latest revision, found here: Downloads - wiiflow - Project Hosting on Google Code
The version with 222 loads los 222 by default, 249 loads ios 249(this one is generally recommended).
Rename the file you download to boot.dol and copy to sd:/apps/wiiflow.
You'll need the sd card in the console to load any .dol file.
Wads only need to be installed if you want to run a forwarder channel from the main system menu, which points to the app on the sd card. One is listed on the Google Source page above, or you can download 4 others along with some themes from the old revision pack here: WiiFlow USB Loader - Downloads