The steps to install Composer
The following steps are entered in a SSH terminal session in the home folder of the website.
sudo apt update
sudo apt install wget php-cli php-zip unzip
Cd /home/ftpuser/RetamaD9
php -r "readfile('https://getcomposer.org/installer');" | php -c php.ini
To run Composer
php composer
Install Git
Another utility used is Git.
sudo apt install git-all