92 Exhaust Cam help

[SilviaS14KA24DE]

Ok, I've searched, and have been confused. I just picked up a 92 (or 93) exhaust cam from the junkyard for hecka cheap. Now the questions:

Do I need to machine the cams? Or can I leave them as they are and install them?

and

How do I install this myself? I read that you have to line the sprocket with the timing chain (mark it, if that eases any confusion).

also

I bought the cam with the s13 sprocket attatched to it (we didn't have a big enough socket to remove it). Can I just leave it on and it will work the the s14 ka? Or do I remove it.

Any clear installation help would be good if someone can. I'm nub that this.

[NISTECH]

bring the engine to top dead center while the chain is still on and in tact. If the old cam is broke remove the cam shafts and the spark plugs first and then bring the crank to top dead center. then install the cams and chains. use a factory service manual to remove and replace the bolts in the proper sequence. as far as the sproket goes I am not sure if they are different I dont think they are.