Partitioning Linux and Android on a Switch with Atmosphere

I am seeing online there are methods of doing this, but I cannot find an in-depth tutorial on how to add Linux and Android to a Switch that already has an Atmosphere. My microsd is 1.5tb. I want to know, is it possible to safely add Linux and Android booting to Hekate without messing with or deleting the stuff I already have? How would I go about doing this?