The best way to attack this job is to have the replacement master cylinder in hand.  You can then position it next to the installed unit and see where things are and how they're aligned.  The two retaining nuts have to be removed and reinstalled by feel.  The actual replacement takes between half an hour and an hour - or more.  I've done it three times and found it to be relatively easy once.  The other two times it was one of the more infuriating jobs I've done.  The basic work position is achieved by lying on your back on the lower door sill, then scooting head-first into the car until your back feels like it's going to snap at about the fifth vertebra - ah yes, now you're there.  Now lie in that position for half an hour or so, rocking from side to side to bruise your rib cage as well.  You could practice by trying to crawl into a dresser drawer on your back, then trying to assemble a wrist watch while wearing someone else's glasses (your eyes are never at the right focal length) while your spouse holds one of your arms in a hammer lock.

So position the new cylinder near the installed one, in about the same alignment to get a lay of the land.  Put a piece of cardboard or a towel down to catch any fluid leaks.  Remove the trim panel - four plastic push pins - the secret is to pop the little center pin out first (I used a pointed Exacto knife blade), then pry the pins out.

First, break the nut for the output line loose (13 mm).  Do this first while the unit is still solidly bolted in place.  Back the nut off a bit.

Release the clip from the pivot pin by prying the end up with a small screwdriver, then push the clip off the pin.  Now you can push the pivot pin out.  Note that there is a rubber o-ring on the left side (the head) of the pin.  This is to suppress rattles.

With the clutch pedal in the released position (up, off the floor), remove the bottom nut using a ratchet and 10 mm socket.  Now remove the upper nut, which is a bit more difficult because the pedal gets in the way - you still want the pedal up though.  A quarter inch drive ratchet is helpful here, although I used a quarter inch drive 10 mm socket with a 1/4 to 3/8 adapter and a 3/8 drive ratchet..  As I said, the pedal makes it a bit difficult to get on the nut.  A short extension might help.

Back the outlet pipe nut all the way out of the cylinder.

Push the pedal to the floor before trying to remove the cylinder from the mounting studs.  With the pedal on the floor, the unit should be easy to pry off the studs.

Compress the inlet hose retaining clip with pliers and slide it back, then remove the input hose.  If the fluid reservoir is full, you will get maybe a quarter cup of  fluid leakage.

Install the inlet and outlet hoses to the new cylinder and install the cylinder on the studs.  Be sure to start the nut for the outlet hose before installing the cylinder - otherwise, the danger of cross-threading will be very high.  Install the pivot pin.  Push the pin against the o-ring and install the retaining clip.  It can be a pain, but keep at it and you'll get it.  It just slides on, but it can be cantankerous.  Try positioning it with pliers and pushing it on with a screwdriver.

Install the retaining nuts.  Check all connections for tightness.  Reinstall the trim panel, then bleed the system.