Clara HD How do I customize my home screen / start menu?

[eloi]

I've never patched or modified my firmware in any way, I tried searching up some keywords before asking but maybe I don't know what the right ones are. I would like to hide the discover function from the bottom bar, and hide "top picks" "shop kobo", and the user guide. also "unread books" which shows I have 4 unread books but when I click on it it's empty.
I recently got rid of +200 books and now I only have 4 books at any given time as a personal preference, and those annoying categories showed up when I did that, if that is of any relevance to this problem. tyia!!