What are you downloading now?
OD is not something you download. It's just the name of the overall group of products that include Windowblinds, Desktop X, etc.
Component Manager is probably what you are downloading now. Continue downloading it and install it. When it's done installing, open it, and you'll see a bunch of applications. Among that you should see Stardock Central. Stardock Central is in beta and will eventually be what will replace Component Manager. It's more centralise and better done. For example when a software is updating Stardock Central will only download the parts that need updating instead of downloading the whole application all over again.
Get it?