photo gallery structure

my site is located here…. https://www.joaniemoore.com/wp

I’m trying to create a structure like this:

PHOTO GALLERY
then a sub category – High School Sports
with a sub category – basketball game # 1
then basketball game # 2

etc

then a sub category – Community Events
with a sub category – snowmobile race
then spaghetti dinner

That sort of thing. When they click on Community Events, they should then see a list of the other events.. I’m not sure how to build this structure…. any ideas?

I started a topic previously but it expired. Thanks!