What do you mean with "Addons" folders ?
- The "Community" folder of the sim, which should contain only a Symlink to the actual scenery files ?
- The "MSFS" folder in the FSDT "Addon Manager" folder, which the Symlink points to ?
Also, if you are asking how to redownload the installer, it seems you haven't paid attention to what your purchase receipt said about download links only lasting a certain amount of time on Digital River, so you had to make a backup of the installer.
If you lost the installer and haven't made a backup, please contact support by email to get instructions to get another copy.
