|You have it wrong way 'round.|
You need to wrap the VLOOKUP() in the IF()
=IF(VLOOKUP(J1,'Main Data'!A:A,2,0)="HC - Magnolia","Found It","Not Found")
Is that what your looking to do?
Check out this page for a quick tutorial on VLOOKUP()
And, in the future, Excel questions are best asked in the Office Software forum.