How do I make my edited clips into a movie?

Click on the little export button (the little square with the upward pointing arrow in it). A dialogue box will appear that gives you several export options. Chose File, and in the next box that appears, choose the destination (i.e, desktop). Then click save and an independent movie will render to your desktop. It may take a few minutes for the rendering to complete, depending on the duration of the movie.

-- Rich

Just to add to Rich's explanation, here you can see the items to select.

In the window that opens, for Quality choose either Low, Medium or High. These names do not refer to the sharpness etc. of the video but to the bit rate. Low uses a low bitrate producing a small file size, which is fine for videos with no fast movement and High uses a higher bitrate producing large file sizes which is used for fast action videos.

Do NOT use "Best" as that produces massive files only suitable for certain purposes and which will probably not be playable on other devices.