Once you check-in at the ME desk, they will direct you to the "Red Carpet" where a CM will indicate which bus line you need to enter.
The times I have used ME, they have had drop-off for 3-4 resorts for each bus. Each resort stop is quite short, so even if you are the last on the list, it won't be that bad.
The time-consuming activities are: 1) Waiting for your resort bus to board and leave (your bus might be there, they might board you, but they might wait for 15 minutes for more passengers before departing the airport - worse case scenario is that you wait 20 min for the bus, board and then wait on the bus for 20 minutes !!!!) and 2) the drive from the airport to WDW property (20-30 minutes)
Once you are on Disney property and stop at the first resort, you are almost there!!!