Spread your refried beans onto your serving plater.
In a mixing bowl mash your avocados together with the garlic powder, salt, and pepper. Spread the avocado mixture over the top of the beans. (If you are using homemade guacamole skip this and make the guacamole and use that)
In another mixing bowl combined the sour cream and taco seasoning together. Spread this mixture over the top of the avocado (or guacamole) layer.If you are adding salsa then spread a layer of salsa here.
Shred the cheddar cheese and sprinkle the cheese over the top of the sour cream layer.
Slice the olives and sprinkle the olives over the top of the cheese layer.
Dice the tomatoes and sprinkle the tomatoes over the top of the olives.
Sprinkle the scallions over the top of the tomatoes.
You can add a dollop of sour cream to the top of the dip if you want to.