What should I do to archive the project file and reopen it in Windows Movie Maker?

Step1：Export your video

Step2: You can select formats and devices. And you can change the name and resolution of videos. Then click on the icon of the folder in the picture and select the location you want to save in the pop-up box.

Step3: When you need to reopen the stored files, click ”+” to import videos, find the file in your location and click open.