I can get the location to a door correct, but I don't know how to raise or lower the door position.
There is nothing in the manual to suggest how this is done with the vertical and horizontal arrows required to indicate where the doors are located.
Well, it's you that are taking from granted the vertical/horizontal arrows should be used to move doors, and of course the manual doesn't say anything about them, because those keys are NOT used to raise/lower doors.
What the manual says, instead (Page 29) is the Slew Keys
are used to move the 3d pointer that indicates the door's position in the 3d space. And immediately after, there's a table with the first two entries indicating what keys are used to Raise/Lower doors, which are the "Slew Up Quickly" and "Slew Down Quickly" keys which, BY DEFAULT (as the table says) are assigned to F4 and F1 keys.
The table is made that way, because you can CHANGE the Slew keys in FSX so, if you haven't changed your key assignment for the Slew keys, they have default values as in the table (F4/F1 to Raise/Lower doors), but if you have, the commands in GSX will follow what you changed in FSX related to the Slew keys.
Assigning keys to GSX using standard FSX functions that can be redefined in FSX itself, it's obviously made intentionally, because you might already defined them in some ways because those keys might be difficult to reach on some keyboards (for example, Numpad keys on a laptop), so you won't have to redefine them again in GSX, which will simply follow your FSX assignment.