does the car turn over at all, or try to turn over? are you 100% sure the battery has enough charge in it to start the car?
It's usually the solenoid that sticks on them. that's the smaller part on the top. hit that with a block of wood/hammer.
The starter motor looks like this

it'll be bolted to the gearbox with 2 17mm bolts which go through the 'box into the engine mount.
to change it you will need to support the engine with a jack. remove the battery positive, followed by the 13mm nut that holds the large cable off the battery to the starter motor. there is also a smaller cable (red/black) that is the cranking wire. remove this. it's usually clipped on. Then remove the 2 17mm long bolts. The starter motor should pull free now. The engine may drop slightly when you remove the 2 17mm bolts and may require raising and lowering to get the engine mount bracket to line up with the starter motor when refitting

it's an easy job. I did mine in 10 mins in the dark tonight
