I am new to After effect.I bought a photo slider project that carry three .mov. I have replace the images but don't know how to view the complete project on .mov or .avi.
As I understand you correctly you are asking How to render a movie file. If that is the case you will find more info here:
After Effects Help | Basics of rendering and exporting
Use the Render Queue to export files | Adobe After Effects CC tutorials
Start here to learn After Effects:
Retrieving data ...