Exporting video via the Avigilon Control Center is a fairly straight forward process. Attached below are the instructions in a pdf document.
Create short video segments as long segments will increase the file size which will take a long time to render the video and will take up more disk space
If there is video you need, it is important to archive sooner than later. You system has finite storage and will overwrite the oldest video with the newest video. How much video saved will depend on the number of cameras, video quality settings, recording rules (continuous versus event driven), and overall storage.