I want to create a simple template which when opened will ask me to fill in a
couple of variables, then place the answer in the document.

I've looked at the "ask" and "ref" fields, but what I need to know is how to
open the document so that the prompts pop up.

This will go onto a Memorandum template. So what I want to happen is that
when I access the document, I'm asked to fill in the blanks (i.e.
"Recipient's name?"), then what I type is plunked into the document in the
right place.