When you installed a sections, templates, themes, styles, page builder and theme builder on your store, you can find them in their respective categories.
For the customize function, deleting the others similar the section.
How To Update The Section?
To update the latest version of section, click Update.
Click the checkbox to make sure you understand what you're doing.
If you want update multiple sections, you can select multiple sections -> Update
Only sections and styles have the update feature.
How To Customize The Section?
To customize the section, click the icon to edit.
How To Delete The Section?
To delete the section, click ... > Delete
If you want delete multiple sections, you can select multiple sections -> Delete
