General Requirements

The following are common pre-requisites for building Electrum-CAT binary for any platform:

Minimum hardware requirements are 8 CPU Cores, 8GB RAM and 100GB of free storage
Ubuntu 22.04 (highly recommended)
Use a sudo account (NOT root)
Ensure Python 3.10.12 or higher is installed
Install git (Ubuntu 22.04 has git installed by default)

Install Docker Image (Ref: guide source)
a) Update Ubuntu package manager and install Docker:

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
sudo apt-get update
sudo apt-get install -y docker-ce

sudo usermod -aG docker ${USER}

sudo reboot

Make a directory for Electrum-CAT source code:

cd ~/ && mkdir catenv && cd catenv

Clone the source code from catcoincore/electrum-cat:

git clone https://github.com/CatcoinCore/electrum-cat.git

Command into electrum-cat directory and checkout master:

cd ~/catenv/electrum-cat && git checkout master