confused about ceiling wires
If I am assuming correctly, below is how to wire it.

Connect all green and bare wires together -- those are the ground wires.

Don't disconnect the black &amp; tan wires in the box. Of those two, the black is the always-hot from the circuit breaker panel, and the white goes to the wall switch.

Connect the single black wire to the black and blue wires on the fan. The black wire in the box is the hot from the switch. The black and blue wires on the fan go to the light kit and fan motor (not sure which is which, but you can safely connect all three together). If you don't have a light kit, connect it anyway so if you add a light kit later you won't have to remove the entire fan to rewire.

Connect the single tan wire in the box to the white wire on the fan. This is the neutral wire.

Since it appears that you have only one wall switch, it will operate both the fan and the light. The way your wires run, you won't be able to have separate wall switches for the fan and light. Instead, you'll need to use the controls on the fan itself for that.

One other thing: if you removed a light fixture, you may need to replace the ceiling box with a heavier duty model specifically rated for fan installation. Most standard light fixture boxes aren't strong enough to hold a fan.

The above is advice based on assumptions. Use at your own risk. Always disconnect the power, and TEST that the power in the box is off using a known good voltmeter or non-contact voltage tester. When I say "known good" I mean that you've tested the tester on a live circuit to be confident that your tester is working properly. If you are in doubt about your abilities, contact an electrician. You can be killed or burn down your house if you make a mistake.