no problem,
Step 1:IF YOU DONT HAVE THE EXPANSION PASS BUY IT FIRST without SXOS not on your SD,TURN OFF AUTOMATIC GAME UPDATES IN SETTINGS AND PUT ON FLIGHT MODE
Step 2: PLACES ALL SXOS contents and homebrew apps on your SD card,Open up checkpoint(if you use that),I use SXOS so i just click A on the photo app on the main screen and move over to homebrew where it is located
Step 3:If you have your own save,go in checkpoint and locate the MUA3 icon,press L to backup and name it something you can readily identify like MUA3 mine
Step 4: Download Doctordooms save
Step 5:Take SD card out of Switch and go through the switch folder or until you find the checkpoint folder,go inside the saves folder and locate the folder that was created from the backup
Step 6: Place Doctordooms folder inside and open it so its just the folder name and saves inside,it is currently a folder within a folder inside,so take the contents out
Step 7:Rename Doctordooms folder to something like MUA3100
Step 8:If done correctly you should have two folders inside the the MUA3 folder that was created,yours and Doctordooms,to know if it has been done right open each folder and you should see sav00, sav01 files etc
Step 9:Remove the sd card and place it back into your switch and go back to checkpoint,from there if you go to the MUA3 icon you should see two file backups,whatever you named yours and whatever you rename doctordooms.
Step 10:Click on doctordooms and press R to restore their save to your switch
Step 11:Get out of the entire homebrew and if done correct open the game and check the trials,hero select etc. VOILA 100% complete save.
Step 12:Remove all contents from your sd card that isn't the Nintendo folder in the main folder when it first loads up
Step 13: Place sd card back into switch and turn off flight mode and put on automatic game updates
Step 14: Enjoy your gameplay with a 100% save of MUA3 with a expansion pass that we will be using in the future
GOOD ENOUGH????