Theres not much to it mate, in short you remove the prop front half, remove the gearstick, split the exhaust, undo the gearbox crossmember and remove it, unplug all the electrical connections and unbolt the slave cylinder. At this point you will need to loosen any tight pipework on the engine and remove the radiator brackets so that you can put a block of wood on a jack and jack the sump up carefully to tilt the engine back, some people hang on the downpipe to do this if its on a ramp or use a lump of wood to lever the engine but I do the jack method. Once the engine is tilted back you can access all the bellhousing bolts and once these are out you can wiggle the box side to side while pulling to get it off the locating pegs, then it's easier to remove the s15 box if you spin it upside down and then take it off, then you're home free to fit the clutch etc and refit is the reverse of removal...