(Following the Blender Guru Donut Tutorial)

So, I have a layout with some donuts (which have icings on top) on a plate, as shown below:
[![enter image description here][1]][1]


In order to add those sprinkles on top of the icing, we went to the "Geometry Nodes" tab, and created some flow. 

Now I'm trying to reuse the same geometry nodes flow to add sprinkles to the plate. 
But to my surprise, when I enter the "Geometry Nodes" tab, everything disappears and only the icings remain (picture below). And I'm not able to make any flow work for the plate.

[![enter image description here][2]][2]


## Question 

Why are the donuts and plate not appearing in Geometry Nodes? (It's not about having a bad node tree! It's simply about "entering the tab" Geometry nodes)

How can I make them appear? (It's like they're simply "not available")   
How can I reuse the geometry nodes for the plate?   

I also noticed that the icings have "vertex groups", while the other things don't.

[![enter image description here][3]][3]


  [1]: https://i.sstatic.net/o5TnU0A4.png
  [2]: https://i.sstatic.net/7oB0mXRe.png
  [3]: https://i.sstatic.net/eGC91ivI.png