Change Companion App Design

How to redesign the companion app ?

I followed this guide
https://groups.google.com/g/app-inventor-open-source-dev/c/Hr91gXZ6jJ4/m/dGTB6JltBgAJ

but when i load aia to my local server it show

The blocks area did not load properly. Changes to the blocks for screen 5383208929591296_Screen1 will not be saved.

Thanks

Did you move the files around so that the directory structure matches what App Inventor expects?

Which file?

I didn't move any files but it shows me this error.

aiplayapp is essentially an unzipped AIA file, except for the fact that the src directory structure isn't correct. We package the companion under the edu.mit.appinventor.aicompanion3 package and the src directory is structured accordingly. App Inventor though expects that packages are of the form appinventor.ai_USERNAME.PROJECTNAME, so you need to move the Screen1.* files to the appropriate directory first before creating the AIA.