You have not got project selected as in the Epic Support document quoted here
How to Revert a Project (If Eligible)
If your project is eligible to be reverted, follow these steps via the Creator Portal:
Open the Creator Portal in your web browser and sign in with your Epic Games account.
Select the Publishing option from the side menu.
Find your project in the list. It should be listed under the Project Type: UEFN panel.
Check if a dropdown menu appears next to the project. If it does, the project is eligible for reversion.
Click the dropdown menu and select Revert to Creative Project.
The page will automatically refresh, and the project type will change to FNC (Fortnite Creative). The island will then be accessible through your golden rift in the Creative hub within Fortnite.
in your video you don’t have “3 Find your project in the list.”
You don’t have any Eligible projects listed for reversion
The only alternative is to use Epic Support answer
The closest you can get to using the in-game tools is to “Launch Session” from UEFN. This opens the project in a Fortnite client and allows you to use the in-game creative edit mode, with changes syncing back to the UEFN editor.