Your download of Columnal version 0.6.4 for LinuxX86 will begin automatically in 5 seconds.
The download is a .tar.gz file. Unzip the full contents to a folder of your choosing, then run the "columnal" executable in that directory. To upgrade an older version, delete the existing folder and unzip the new folder in its place. (It's important to make sure the full contents of the old folder are deleted.)
Columnal is currently in early access, which means the design is still being worked on, and the last few kinks are being ironed out. If you have any problems or suggestions, drop an email to firstname.lastname@example.org where we will be happy to hear from you.