If you are off campus, you will have to use VPN to access grok. Missouri State University provides instructions and software for Windows, Mac, and Linux on its Virtual Private Networks web page. The following instructions assume that you are running VPN if necessary.
For Mac and Linux users, just open a terminal and type "ssh username@grok". For Windows users, download grok.zip, unzip it somewhere (I recommend a USB flash drive for portability), and double-click on grok.cmd within the grok folder. You can also run PuTTY directly by typing "putty username@grok" at the Command Prompt (assuming that PuTTY is in your PATH), or you can double-click the PuTTY executable and fill in the blanks. The version of PuTTY and related programs included in grok.zip is from here, and has the advantage that it stores configuration and session information in files rather than the Windows registry. When you're running PuTTY, you can change settings like font and window size by right-clicking the icon on the left side of the PuTTY titlebar.