At my graduation ceremony, all the students collected their gown in a store room. We then just slipped them on top of our outfits and that was it.
You should find out what the process is at your university, it differs per uni but usually you pick it up there.
Thank you for the reply. I will send them an e-mail.
You'll have to queue to collect your gown, but if you're hiring (which most people do), it's usual practice to collect it promptly before the ceremony. There'll be a system, as hundreds of students are processed on each graduation day, so just identify the system of your specific institution.
When you pick up the hired academic gown/cap, it will be handed to you either at or very near the venue an hour or two before the ceremony. You travel there in your own smart clothes and you won't gown-up until you're with hundreds of other people all doing the same. You hand it back after the ceremony, before you go home.
At my undergrad uni it was traditional to go out of the venue afterwards and take some informal group snaps and selfies with mates at some landmarks a few minutes' walk from the ceremony venue, but there was no obligation to do that. Even if you decided to do it, there were plenty of others doing the same, so there was safety in numbers.