Closed Compositor, Now Can't Find Nodes

I had opened the compositor using ctrl & left arrow. Afterwords I closed it to continue other things. Now ctrl & left arrow doesn’t open the compositor but opens dope sheet instead. When I manually try to open the compositor there’s no nodes there. What rookie mistake am I making?

To make more sense of what I am talking about, I’m watching “Create a 3d Animated Title using Blender” by Blender Guru… I made it to 27:30 and then that’s where I can’t find the nodes

Check the drop down menu at the top for Screen Layout. You can choose the type of tool layout you need.

Also is it possible that you have more than one scene? Sometimes you change scene and all of the settings seem to disappear. Just swap scenes in the other drop down menu.