Install osTicket on my Cloud Ex2

Hi,
how can I install a 3rd party app? It’s osTicket from osticket.com.

thx
Andre

Instructions related to manually installing 3rd party apps on a WD My Cloud EX2 are available in the unit’s user manual, page 99 (104).

I know this manual. But there isn’t described how to install a special app like a php package.
What format should it be: zip, tar, gz etc. Can the package be stored on my PC? I want to install a ticket system or another groupware