How to set the default desktop as "Dim Sum Desktop" on vivo X9: First go to Settings - More Settings - Applications - Default Application Settings, and select "Dim Sum Desktop" on the desktop as the default desktop. Then go to Settings-More Settings-Security-Change System Desktop, turn on "Allow Desktop Change", and turn off "Home Key to Lock System Desktop".
Specific steps:
1. Click Settings on the standby desktop
2. More settings
3. Applications
4. Default application settings
5. Click "Dim Sum Desktop" on the desktop to set it as the default desktop
6. Return to the more settings interface and click Security
7. Change the system desktop
8. Turn on "Allow desktop change" and turn off the "Home screen key to lock the system desktop" switch