Creating a new Multicell fixture

I want to create a new Mulit-Cell fixture with a master and 6 simple INT cells (I guess)

The only instructions I have found tell me, after pressing the [Create Multicell] button then press [+] to add  cells.

It then goes on to talk about fixtures in my show, making copy as cell and so on. It also mentions creating a new cell profile whereas my prompt says "Fixture"

Can some one guide me to place with clear up to date instructions?

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