Once you have a memory card with the right save file of SD Remix Lite for your version of SSBM, you need to follow the following steps after booting up SSBM to enable/activate SD Remix:

1. Go to the Main Menu screen, then select Versus Mode, then select Name Entry.

When you go into Name Entry, you should hear the announcer exclaim “Success!” and you should go to the Name Entry screen with the only name saying “SDR-LITE-PRESS-B” or something to that effect.

Press “B” to exit the name select screen. You have now enabled SD Remix Lite! If you go back into the name entry screen, you should be able to edit name tags like normal. You will have to do this each time you boot up your console into SSBM, much like how with Project M you need to go into the stage builder every time you start Brawl. Just like normal SSBM, you can run multiple setups off of one memory card.