I suspect that there isn't many write ups on how to change the convertible top fluid because normally it is a "fill for life" item. The Ford service manual doesn't even have a procedure to "change" the fluid.
There is a procedure in the Ford Service manual to bleed the system after a repair.
OBTW, the system uses Mecron automatic transmission fluid. It is OK to use Mecron V.
I guess if y0u are intent on changing the fluid, the lines could be disconnected from the pump and the fluid allowed to drain into a catch can.
New fluid is added through a rubber fill plud on the pump itself. Add the fluid to the bottom of the fill hole. It may be necessary to raise and lower the top several times to bleed the air from the sytem.