5 things i learnt about Sandbox folder structure:
- Everything mentioned in the videos applies to both the free SDK and also the MOD SDK
- the code folder contains examples, and scripts
- the Editor folder contains all editorial elements such as icons
- Game folder is the most important. PAK files are stored here: which contain animations, CGF files, sounds, particles, materials and textures.
- the tools folder is the most important. To make new comments make a new folder named 'user.cfg' 
- extended plugins should be exported to 3D studio max, photoshoip and maya