What you need to do is rotate the engine (clockwise as you look at the crank pulley) so that number 1 (the cylinder nearest the cam-belt) is at TDC. It's easiest to turn the old donkey over if you take a plug out of each cylinder (and since you're servicing it, you'd want to have a look at the plugs anyway, isn't it?
You can use the floating screwdriver method to get a rough TDC: Stick a thin, long screwdriver down the spark plug hole and then watch it as you rotate the engine. When it's at its highest point, whip off the rocker cover and look at the inlet cam lobes for number 1. They should be pointing backwards. If they’re pointing forwards then #1 is on it’s exhaust stroke, so rotate the beast another 360 degrees.
Once you got TDC on #1 the cam-locks should fit.
One goes over the inlet cam lobes on #2 cylinder.. the other one goes on the exhaust cam lobes on #3.
The main thing is the locks can only go on one way. On the inlet, the cut out should match up with the cam lobe and the holes in the lock should line up with the holes in the head that the journals bolt into (you have to remove the journal to put the cam block on).
If everything lines up and the lock can be bolted to the head, then it fits. Hopefully the other one will then fit on the exhaust cam.
If they don’t fit or line up perfectly (bearing in mind any minor deviation between cam lock and cam lobes.. seriously - less than a millimetre
of lash that can be adjusted by tweaking the cam pulleys on their bolts) then they’re not the locks for your motor.
From memory.. try C1 on the exhaust and C2 on the inlet.. but it should be immediately apparent which is which. There’s a picture of what you should roughly look like (a 2.0ltr is shown) on The cam variator