I just pushed a series of commits, you can now;
1. scan a set of folders for ergs and videos (tools->scan for..)
2. import an erg file by selecting it (tools->import workout...)
3. Drag and drop an erg or video.
If you import/drag a video we only add a reference to it -- we don't copy it, since they are so big. We do copy workouts since they are small.
You can remove references at the same time you set search paths and scan using tools->scan...
If this sounds too complicated don't worry about it. Drag and Drop should keep most people happy without having to think.