The Snap utitilies are often already installed on many Linux distributions, including later distributions of Ubuntu. If not, you can often find it on your package manager.
Alternatively, if you use apt:
Once you have snap, you can proceed to install Vagabond:
You can access the GUI through vagabond.gui and the command line-only version of vagabond using vagabond.cmd. The cluster4x GUI is available through cluster4x.