Each theme will have various building blocks that differ from theme to theme. You can use the theme editor to customize how each block looks.
To customize your building blocks, navigate to Customization and click Customize.
On the Storefront home page section, have selected the Theme home page option, then click on Customize directly below it.
On the left, you will see the available blocks for your current theme. Read carefully over each section, and as you make changes, the page will automatically update on the right.
Most blocks will have a toggle to hide or show the block, so feel free to disable any blocks you don't want to show on your homepage.
If you'd like to remove specific parts of a block or maybe add blocks from another theme, you'll need some HTML/CSS/Liquid knowledge,e or you can hire a third-party developer.