Cannot preview in this file - active scheme does not build this file : SwiftUI on Xcode 11 in CatalinaOS

Question

I opened Landmark App using SwiftUI on Xcode 11 in macOS Catalina(10.15) and while opening the Canvas Editor for .swift files containing SwiftUI is showing

Answer 1

In the schemes I was able to select, it contained only one scheme. Reopening the folder in a folder that's not in the Downloads directory made live editing work for me