1. Find an image of the film strip
2. Create a new composition with the dimension of the film strip
3. put your video file or whatever you want on the blank spaces in after effects with position tool (you might want to use mask tool to fit it in exactly)
4. Pre-compose the film strip together all the layers you put on the blank spaces and change settings of video project back to what your working with (probably 720p since it's you)
5. use the position tool to move the pre-composed layer

AKROSS

the project
6. Enjoy
additional note: you might want to turn on motion blur to make it look nicer
Shortcuts mentioned:
Precompose: (crtl+shift+c)
Position: p
Setting composition settings (right click, change comp settings)
Mask tool: g