A solenoid performs two functions but think of it first as just a big switch that connects your battery cable to your starter. This is how to check it:
See if it is receiving 12V at the small terminal when you turn the key as described above. (Use a bulb and a couple of lengths of wire you dont have a meter)
If it is, turn off the ignition. Then jumper the two large terminals on the solenoid. If the starter spins, you know the solenoid isnt working.
(The other function of the solenoid is to engage the starter gear with the flywheel ring gear)

You dont HAVE to turn off the ignition but if you have got your head anywhere near the engine and it fires up you are in for a bit of a shock.

You dont have a starter relay as you have a manual and your clutch switch isnt in use anyway. Later cars have a relay as part of the immobiliser but I think your car is too early for that.