metering head stays in place as the box come out from the bottom.
anti roll bar off
starter motor off
abs belts/modulators off
clutch/speedo cable off
driveshafts out
support engine with some form of jack or from the top
then undo the gearbox cradle
lower engine/box together then slide gearbox off
there are probably bits ive missed.
i swapped a gearbox on my tubo a few months ago and i have never done any work on a car before really (apart from oil change etc)
what i will say is get a Haynes guide as thats what i used and its pretty straightforward.
out with the old
in with the new
if you have any problem while doing it then you can send me a pm if you like and i will talk you through it in more detail