added info about finding a command line interface

README.md

@@ -48,8 +48,37 @@ things.
 
 Because of this, you will need to use your UNIX-like environment's
 command line interface. For me, it's a little icon on my desktop that
-looks like a blank, black screen. You'll be using this little,
+looks like a blank, black screen, but it may be different for you. I
-mysterious interface throughout this handbook.
+will list off how you can find the command line interface for a few
+operating systems below:
+
+**For macOS users**: You can use one of the following procedures below
+for finding the built-in app called "Terminal":
+  * Open the Spotlight app and search for the word "terminal"
+  * Open your `Applications > Utilities` directory and double-click the Terminal app
+
+**For Windows Subsystem for Linux users**:
+  * Open your start menu and search for the word "Ubuntu"
+
+**Note**: The steps above assumed you chose Ubuntu as the Linux
+distribution for Windows Subsystem for Linux during your installation.
+
+**For Ubuntu users**: You can use one of the following procedures
+below for finding the built-in terminal application:
+  * Type `Ctrl+Shift+t`
+  * Click the Ubuntu icon and search for the word "terminal"
+
+**For cmdr users**:
+  * Open the cmdr application
+
+**For PuTTY users**:
+  * PuTTY isn't a command line interface itself, but it acts as a tool
+    to connect to other computers, so you can use their command line
+    interface. This will be covered in the
+    [Connecting to tilde.town](#connecting-to-tildetown) section.
+
+After you think you have found your environment's command line
+interface, you'll be using it in the rest of this handbook.
 
 **Note**: I'll be calling the command line a "terminal" from now on.