Triple-click the word "telnet" in the line below on this page to select the whole line:
telnet pop.centurytel.net 995
Copy the selected text to the Clipboard by pressing the key combination command-C.
Launch the built-in Terminal application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad and start typing the name.
Paste into the Terminal window by pressing command-V. I've tested these instructions only with the Safari web browser. If you use another browser, you may have to press the return key after pasting.
You should almost instantly get three or more lines of output below what you entered, one of which is this:
Escape character is '^]'.
If there's no output within ten seconds, consider that a failure. If you get something different from the above, please post it in a reply. You can then quit Terminal.