Here is the diagram for the fan/dimmer control. There is 12/2 wire at the ceiling and the switch. Does this mean I wire the black to black, red and yellow to white, and green to green by this diagram?
In order to answer the question we have to know which wire in your switch box is hot. That's why others here have asked for pictures of the wiring in the boxes. Typically if you have only one cable in the switch box (12-2) the white wire should be the hot and should have been re-identified as hot using black tape or some other permanent marking method, but this isn't always done to code. My guess is you've got more than one cable either at the switch or at the light box. If there are more cables at the light box, look at the wires and see if there is one white joined in with one or more black wires. That usually indicates the white wire in your switch box will be hot. To answer your question about reading the diagram, the black will tie to the hot in your switch box, the yellow will tie to the switchleg going to the light, and the red will tie to the switch leg going to the fan. From your description it sounds like you do not have enough wires in the switch box to control both light and fan (if you only have 12-2). You may have to pull another cable up there to get the wiring you need. Anyway, back up at the light box, you say the fan unit has blue, black, and white wires. The blue wire is for the light kit on the fan, the black wire goes to the fan, and white of course is for the neutral(return path) for both light and fan. Normally the blue and black can be tied together and run on a single switch, but you wouldn't want to run the fan motor with a dimmer switch. Alternatively, they do make wireless kits to control both light and fan independently with a remote control. The receiver mounts inside the fan canopy and parcels out your instructions to the fan and light. They are a pain to install, though, and if you go that route you have to make sure it will work with your brand and model.