Before getting to know the screen's layout, take a look at the detailed structure of the project in VideoStew. The editing screen exists to easily create and modify the content you want.
By default, a project consists of multiple slides, and each slide contains several elements.
The editing screen is for editing a single project, so the project is the highest-level concept. If the Home Screen is for managing multiple projects and additions, the editing screen is a space for creating and modifying a single project to taste.
A slide contains several elements. Text, videos, images, etc. that appear on the screen are all considered elements. On the editing screen, you can add, modify, or delete these elements.