Open a terminal in the folder containing the download and run:
sudo apt install ./Framecut_1.4.2_amd64.deb
Then launch Framecut from your applications menu.
A couple of useful things.
Already have Framecut?
Open App updates inside Framecut to check for a newer version. Windows and AppImage installations can update in place. For a .deb installation, download the new package and install it again with your package manager.
Do I need to install any extra tools?
Framecut includes the media tools it needs to download and export clips. You don’t need to install yt-dlp or ffmpeg separately.
Linux video preview isn’t playing
On Ubuntu, Debian, or Linux Mint, the embedded player may need system media plugins. If the preview does not play, install these packages and restart Framecut: