OpenShot is a free, open-source video editor for Linux. Here is some notes during I used it:
You can add media files(video, audio, photo) into a project.
You can create multiple tracks which contain the media items.
The media items in a track with higher ID will override the ones in the track with lower ID.
Use “Razor Tool” to cut the media item, use “Resizing Tool” to resize the length, use “Snapping Tool” to make items seamless connect as one automatically.
You can add subtitles into the video. You need ”Inkscape” being installed to enable the advanced subtitle properties editing.
OpenShot supports a lot of format to export the video.
You need a powerful computer(CPU) to do the final exporting.