Intrearms mark X safties

Question
I have an Interarms mark X that I used for metallic silhouette competition back in the late 70's. I had someone restock it for me as a single-shot in a fiberglass stock. When they did it they removed the safty. I now wish to convert it back to a convential rifle with safty. I ordered a safty from Interarms because I don't have the original one.They sent me four parts, a small spring, a ball bearing, a screw, and the sliding safty piece, but no instructions. I assembled it in what appears to be the correct manner, but it doesn't work. I don't know if i'm doing it wrong, or if they didn't send me all the pieces, or whatever. Any assistance you can give me will be greatly appreciated. Thank you.

Answer
I would take it to a local gunsmith.
Any competent gunsmith can add a safety.

Mark X is Yugo. made Mauser by Zastava.
http://www.zastava-arms.co.rs/english/civilni.htm
You can try contacting them.

Interarms went out of business in the early 1990's.
I am not sure who you bought the parts from.

You can get a schmatic and possibly parts from Gunparts.
http://www.e-gunparts.com/