I'd offer pretty much the same directions but here's a little more detail.
When exiting the airport property look for the signs directing you to the North Exit onto route 528. At the 528 interchange go West on 528 to I-4. At the I-4 interchange be sure to take I-4 West (I think it'll say Tampa). At exit 68 stay to the right to turn right but get into the left right-turn lane (there are two right turn lanes, just don't get into the right most lane). Once you've turned onto SR 535 after the exit ramp, move over to one of the left lane but don't get all the way over into the first left turn lane. After the first opportunity to turn left (I think it goes into a gas station, maybe also a hotel) get into one of the left turn lanes and turn left onto Hotel Plaza Blvd.
As noted by the PP, continue to the traffic lights at the end of HP Blvd. and bear slightly left onto North Buena Vista Drive. Stay, or get into the right most lane and turn right (not left as PP advised) into one of the DTD parking lots.
Downtown Disney is a nice place to spend some time before checking in at your resort.
Dick Taylor