First of All Before Anything Make Sure you Have Enough Storage from Settings -> Storage Then Check How Much
Free Storage do you Have ? At least You Should Have Between 15GB -> 50GB Free Storage For Roms
Go to Play Store and Download and App Called "ISO Craft"
After You Open the "ISO Craft" Click on The
Then Click on "Add Files" Then Choose All the Files You Want to Move
After you Finish Click on The and Click on "Save ISO File"
Then Choose The Path for The ISO fILE You Created
Import the ISO File You Created From Here