@faroud Which edition of ZorinOS 16.2 are you attempting to install using a DVD e.g. Pro, Core, Lite etc?
Can you edit your forum profile to indicate that. It will remove the need to ask the question again in the future.
Note, some editions of ZorinOS are too big for a DVD.
Make sure you get a USB stick large enough. I would also suggest you avoid Balena Etcher to burn your USB and use Rufus or Unetbootin in preference. Balena has poor reputation of wrecking USB sticks, according to posts on the forum.
Also is your computer 64bit or an older 32bit machine. If you are trying to install a 64bit OS on a 32bit machine it will fail. See this Cannot boot from DVD - #6 by jgordon