I've Done two of the levels
First is Baldi's Secret Super School
For RAR users https://www.mediafire.com/file/vjhor26jsq1ek8v/Baldi's+Secret+Super+School.rar/f...
For ZIP users https://www.mediafire.com/file/1mcxoetl74zi5oz/Baldi's+Secret+Super+School.zip/f...
Second is Unfair School
For RAR Users https://www.mediafire.com/file/lbzvvcta30nxqos/Unfair+School.rar/file
For ZIP Users https://www.mediafire.com/file/cnqhvkqnktno84k/Unfair+School.zip/file
Installations Instructions:
For PC users: Make sure you extract the file then go to this location C:\Users\yourpcname\AppData\LocalLow\JohnsterSpaceGames\Baldi's Fun New School Plus Ultimate Edition\Floor Customizer and then put the folder here After you're done launch bfns+ then click on game mode and click on floor customizer and find the map from the right side and you should see the map you installed
For Android users: go to android/data/com.johnsterspacegamesbaldifunnewschoolplusultimateedition/files/floorcustomizer and the custom floor is need to extracted (but if you need zarchiver good luck) paste on floor customizer and done! (credits to principal gaming for the tutorial)