Click on the Linux button.
Save FormikoLauncher.deb as a file.
Press the Windows/Linux/Mac key.
Write cmd & launch a terminal.
Write "ls" then press enter. You now can read the name of your downloads folder in your computer language.
Use the "sudo ..." command from the web site by replacing "Download" by the name of your download folder.
Press enter.
Launch game by writing "formiko" then press enter.
Wait for last version to be downloaded
Choose your language
That's it!