Some help with Photopress please

Can anyone tell me how Photopress works?
On this page: https://siteground129.com/~raphaell/?pp_album=main&pp_cat=
I have what apparently lists categories. I expected that since there are 3 images if you click on that category they would display, but no, it just reloads the same page.
So how can I get all the imgages to display?
Also, how do you delete categories? I saw a post about going into PHP MyAdmin but is that really the only solution? I have MySQL and don’t see how I can delete users.

It’s frustrating because Photopress seems to be a great plugin but there’s no support forum.