Like the newbie that I am, I attempted to drag Applications to my dock but it disappeared! How can I get it back into Finder and also on my dock? Thank you for your help.
Or, if you want an alternative way... Open Finder > click on Macintosh HD (or whatever you've called it - but its probably the first listing on the left in the sidebar) > locate the the Applications icon, and drag it to the sidebar of the Finder. Then, drag it again to the right side of the dock. You're not "moving" it, just creating an alias in the sidebar and the dock. Do note, that if you drag the applications folder to another folder you will likely be moving it, which may cause problems. So, once you have it in your dock and sidebar, avoid the temptation to see where else it might like to go.