Here is how I have set up my Edmodo this year. I have a folder for each concept and then I post teaching videos, songs, and games to help students with the specific concept. I have found this to be a great tool to use during the classroom. It makes finding things on Edmodo much easier for students and they like having everything they need in one spot.
Another website that I tried out is now called padlet. It seems like a great site for organizing files for students. This could be a fun engaging way to have students organize information for a project. I made an example which shows steps for order of operations and also links them to a video of it.
Order of Operations Page