This is a very simple one time process. Mod Organizer will automatically log into your Steam and Nexus accounts. The set up is very easy just follow these steps. Oh and no worries your personal information is not shared.. It is only for username and password storage.
Now let’s see if it works, select the Skyrim Launcher from the drop down menu and click run. Note if you are subscribed to any mods on the Steam Workshop they will be downloaded into Mod Organizers overwrite folder. This will be explained fully later but best for now to unsubscribed to any mods you may have previously done so before installing MO.