I am attempting to make a timelapse, with music playing in the background. However, upon dragging in the latest few audio files, I have found that they don't go where I dragged them into, forcing me to move several different files about within Movie Maker whenever I import some more music. It may be because I was dragging them in from a File Explorer window instead of from the desktop, but that may just be me being desperate to find out how to avoid this issue in the future. 

In case it helps, the video is currently at a length of 1:09:49:25 (H:M:S:MS) and all the footage except for the first 46 seconds or so.

If this issue can't be avoided, please suggest a different (preferably free) video editor I can use.

Thank you.