So, according to my book, to make masa you should use:
5 cups masa
2 sticks of margarine
2 cups of vegetable broth
When I did it this time, it seemed a bit too dry; so when I did Round Two of tamales (dessert ones) I changed the ratio to 4 cups masa: 2 cups liquid.
So... in your mixer, blend up the margarine and a little of the masa until it is smooth. Then add more masa, and broth, until it makes a nice spreadable dough. Also add in 1 tsp of salt.
Then, lay out your other ingredients. For me, this was to chop up the chiles and olives, marinate the tofu for a couple of hours, mix up some frozen corn and canned black beans, and cut some cheese into strips.