OpenShot Video Editor is available on most operating systems (including Linux, Mac, and Windows). Visit the official download page and grab the latest and greatest version: http://www.openshot.org/download/.
Depending on which Linux distribution you use, there are likely many ways to install OpenShot. The easiest way to ensure you have the very latest version, is to download an AppImage from the project website (listed above). Once downloaded, right click on the AppImage file, choose Properties, and mark the file as Executable. Now, go ahead and double click the AppImage to launch it.
Download the DMG file from the project website (listed above), double click it, and then drag the OpenShot application icon into your Applications shortcut. This is very similar to how most other Mac applications are installed. Now launch OpenShot from Launchpad.
Download the Windows installer executable from the project website (listed above), double click it, and follow the directions on screen. Once completed, OpenShot will be installed and available in your Start menu.