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.
sudo dnf update
sudo dnf install snapd
Alternatively, if you use apt:
sudo apt update
sudo apt install snapd
Once you have snap, you can proceed to install Vagabond:
sudo snap install vagabond
sudo snap install cluster4x
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.