The tools provided in the guides will do it for you. Follow this guide in order to setup emuNAND on your Switch.Do I have to create a separate partition on my SD card for emuMMC stuff, or can I just create emuMMC without doing any of that? I will be using both emuMMC and sysMMC on the SD card.
Additionally, for game backups to work, you can install sys-patch module as well. Optionally, you can install Tesla + nx-ovlloader as that will allow you to see whether sys-patch is working properly, after you press L + D-pad Down + R (Stick) combo, select sys-patch,