Can't install Gnome desktop environment

When I try to download environment through Synaptic, Zorin shows me the dialog above.
How to solve problem?

When you first fire up Synaptic (do not run any Search), on the left sub-window, under “All”, there should be listed “Broken”. Click on that and then it will list packages that you can select to Fix. See last screenshot here: Installing packages using Synaptic Package Manager GUI

I arrived to this point, and what to do now to fix broken package?

Can you right click on it and see what options there are to Fix it? I’m pretty sure it should just say Fix. Sorry, it has been a while since I had a broken package and I do recall that right click allows you to Fix it but don’t remember what the choices are.