Logging into the website now automatically grants you access to the file sharing space (and vice versa).

You can find the season series files in the new Series folder in File Thingie. We're also working on a similar feature to cover our past Events. To use a "replay mod" (as we'll call them): download the desired zip file, consult the "Schedule Guide" Excel file, install the appropriate mod for the series, and then unpack the zip file archive into the corresponding mod folder.
You may find it helpful to build a "duplicate mod" so as to not interfere with your current files for that mod.