1. You’ll want to use post “Categories”. When adding your post, you’ll see a “Categories” metabox on the right side of the page where you can add new categories.
Once you’ve added some posts to a couple categories, go to “Appearance > Menus” and choose the “Categories” module on the left side. There you can select your created categories and add them to your menu.
2. This plugin allows you to swap out menu locations on specific pages: https://en-ca.wordpress.org/plugins/menu-swapper/
3. First, create and publish your page in the “Pages” area. Then go to “Settings > Reading” and select “A static page” under the “Front page displays” option. Then select your created home page.
4. If you have GP Premium, you can use the Typography add-on. Go to “Customize > Typography”. The paragraph size can be set in the “Body Typography” section, and the H1 size can be set in the “Content Typography” section.
Hope this helps 🙂