The latest and greatest version 6.7 of Ardour, the open source DAW for Linux, Windows, and Mac is released. See the release notes, and download a readily compiled version for an amount of your own choice (starting at 1$). As a supporter I have it already. There are also a manual and a tutorial. That latter one is some years old already, but still useful if you’re new to recording multitrack audio with a computer.
Thanks to Paul Davis and to his team.