Here's what I've been using.
#place osTicket-v1.10.zip into the ~ directory
sudo apt install unzip lamp-server^ php-gd php-imap php-xml php-mbstring php-intl php-apcu -y
unzip osTicket-v1.10.zip
sudo rm /var/www/html/index.html
sudo mv upload/* /var/www/html
cd /var/www/html
sudo cp include/ost-sampleconfig.php include/ost-config.php
sudo chmod 0666 include/ost-config.php
sudo service apache2 reload
sudo service apache2 restart