This script work 100% with clean Debian & Ubuntu box
wget https://github.com/waelisa/Transmission-seedbox/raw/master/install-transmission.sh
chmod u+x install-transmission.sh
./install-transmission.sh
Now you can use your server ip http://SERVER-IP-OR-HOSTNAME:9091/transmission/web/
Download Transmission Remote GUI https://sourceforge.net/projects/transgui/
Note: If you don't have zlib try sudo apt install zlib1g or sudo apt install zlib1g-dev