How do I set timing when distributor is replaced --not by me. .

My distributor was replaced by some one else> not me.  So, I do not know if the distributor was installed at proper time. Engine won't start but fires when I crank it. I cannot locate any marks on damper pulley to set timing by. I want to set distributor by timing marks for TDC, but can't find any marks only degree scale on timing cover.