Steps for setting up sandbox Environment

go to - Xcode -> Product -> Scheme -> Edit Scheme -> Click on Run (on Left side) then in Option Tab set the "storekit Configuration" to "None"

in your device you need not to logged out from the current Apple ID , just go to settings -> App store -> and add Sandbox ID (you have to create at your Apple developer Account)

and run the project from the xcode now, your sandbox environment is ready