No "Split Staff" Option

I really hate MuseScore 4 but I'mm pretty much forced to have to learn how to use it anyways. In MS 3 at least you have the option of splitting the staff, but in MS 4 you don't. I want to make a piano score that has 3 staves and I cant seem to figure out how to do it n MS 4.

Overall, MS 4 is awful, and they should stop trying to over simplify everything.