Definitions & reducing footer area

First off, Thanks so much for a great theme! It is working out quite well for my webpage to showcase my Art and some photography. I am very new to this and your theme helped make it a lot easier.

I do have a lot of questions and I guess the biggest problem I am having is finding out the definition of each area that I need help with. It is hard to perform a search on “how to make that space at the bottom above the footer” smaller. (I would like to attach a screenshot, but not sure how)

This is my page:
https://www.harleyarts.com

Is there a website that gives the names for each area on a theme?

I would like to find out how to reduce the size of that blank space at the bottom above the footer where the up arrow is, or how to make use of it somehow?

I don’t know code very well, and when I do find any suggestions people give on themes I am not sure if it is directed just for their page in general, or if it will work on all webpages. I am just going to have to learn it I guess! lol

Thank you! ??