How do we switch desktops?

I thought this would be straightforward, but been struggling with this - I’ve installed both Mate and XFCE and want to switch between them. How do I go about doing that? Even went as far as uninstalling XFCE but just cannot boot into Mate.

Going from: http://unix.stackexchange.com/questions/243195/what-desktop-environment-does-startx-run-and-how-can-i-change-it

You can specify which binary (desktop) you wish to run from terminal:

startx /usr/bin/startkde

So mate is gnome, should be (not tested):

startx /usr/bin/gnome

Maybe XFCE is (again, not tested, you might need to search for the binary):

startx /usr/bin/xfce #or xfce4