Many to many relationship

I wonder how to accomplish the following with DataAssist:

1. I have an eductaion site where users/students should be able to access different media (pdf and mp3 files etc). Some files should be accessible to all users, some to just a few and so on. I have set up one MySQL table named "users" for all the userdata and one named "media" for the media files. I have also created a inbetween table consisting just of 2 fields, UserID reflecting the user table primary key field UserID and MediaID reflecting the media table primary key field MediaID.

2. I have built all the login, logout, registration functionallity for users with SecurityAssist and it works great now. I have also built an administration section with users update and file uploading to the media tabel in database.

3. A user who logs in successfully is transfered to the students page where he/she should be able to access his/her registration information and mediafiles which he/she has access to. I want to be able to show/list only certain files for different users but don't know how to accomplish this?

For example: Several users should maybe have access to the same mediafile and sometimes just one user should be able to access a certain mediafile. For what I have learned I need to have the Many-to-many relational table I described above to achieve this? I just don't understand how to set this binding up on the page? Someone please give me some input in how to achieve this!?

/Martin Johannesson