Heat all of the sauce together until heated through

Use a 2 quart or similar casserole dish:

Layer 1: tortillas
Layer 2: sauce
Layer 3 cheese

Repeat twice, put heavier cheese the bottom two layers, and lighter on top

Bake at 350 degrees; if not from refrigerator 20-30 minutes

You can cover for first 20 minutes, but it's not necessary