Gear box change?

[Little Rascal]

Hello all - i'm expecting my new gearbox for my bedford rascal romahome to arrive shortly but I need some advice with fitting it. firstly how do i do it? i presume i just empty the old 1, take it off, put the new one on and then put some oil in it and connect the cables?
any tips or advice would be brilliant.
Also i need to know what type of gearbox oil it would take, does anyone know?
mat

[Little Rascal]

cheers towie for your help.
unfortunately i've already gone through the agony of changing the gearbox, and i made a mistake by not lining it up correctly. it's going in the garage tomorrow, and also havin the clutch replaced. as you say, it's worth changing it while the gearbox is off.
mat