VLOOK-up without N/A and 0 results (extraction from 2 sheets)

I am trying to create an if-vlookup that retrieves data from 2 sheets with following specs: - if the retrieve from the 1st sheet shows N/A and 0 results than vlookup from the 2nd sheet; - if the the 2nd vlookup retrieves N/A and 0 results than change them with blanks.

Thank you in advance !