If you see vacuum only and no boost reading on the gauge, sounds like its connected in the wrong place. I'm not sure what would have vacuum and not see boost though, unless there is an issue with your boost...

 

its normal unless you're in gear and apply engine load then you should start to see real positive boost pressure. Just revving in neutral the highest your boost will go is 0 or just barely above. Otherwise it should be 0-20 inch/hg.