...

If you (as the professor) want to log into WeBWorK via Moodle, you need to first manually create a WeBWorK account using your Swarthmore email as the login name and permission of level of professor.  Once this account is created, you will be able to log into WebWorK via Moodle.  You may want to have two accounts for yourself: one with your username and with with your email so that you can log on both ways.

Setting up a single link between Moodle and WeBWorK

• Set up your WeBWorK course
• Go to your Moodle course, click the gear icon, select "Turn editing on"
• Click "Add an activity or resource" link, select "External Tool" and click "Add"
• Give the link a name such as "WeBWorK"
• Under "Preconfigured tool" select "Automatic, based on tool URL"
• Click "Show more..." to show all the configuration details 
• Under "Secure Tool URL" copy and paste the URL for your WeBWorK course.  The format should be https://webwork.swarthmore.edu/webwork2/<CourseName> (where <CourseName> will be your actual course name)
• If you'd like the grades for all the WeBWorK assignments to be entered into the Moodle gradebook, complete the "Grade" section.  Otherwise change the "Grade" type to "None".  
• Save your settings

...