The best part about using Linux is that most of the software available for Linux are open-source and free. So, if you are just getting started OpenShot can be a very good option for you. OpenShot is an incredibly good free video editing tool. Its interface is clean and easy to get around and is backed by a great set of professional video editing tools including 3D-rendering, video effects, animations, keyframes, and more. Despite being open source, the software is constantly updated to bring you new features and smooth performance. The software is built on powerful FFmpeg library hence it can read and write most video and image formats. For a Linux user, OpenShot is a great place to start.
In case that you don't want to upgrade to Windows 10, you can still find installation packages of Windows Movie Maker on some third-party authoritative download sites. (Windows Movie Maker has been discontinued by Microsoft, remember to download it on your trust download sites. ) However, you must know it won't upgrade anymore, so you are not able to enjoy some innovative and high video editing technology.