Edit Links?

I thought it would be easy, but it was not. Trying to link with an Excel spreadsheet,
I'm advised to click "Links" on the Edit Menu. There is no such choice. Within
the variable table, the right-click choice for "Edit Links" yields only greyed-out
buttons. How do I link with an Excel spreadsheet. I thought it would be a great
idea for setting up a bill of materials using dimensions from the variable table.
Thanks . . .
John Hilgenberg