Inventor Resources

So I  had a question about constraints in Inventor as they were a bit confusing to me. This video I found was a great help:
http://www.cleanvideosearch.com/media/action/yt/search?button=Search&videoId=&totalNumberOfItems=0&currentRowNumber=1&sortByCriteria=0&orderAscending=false&searchFilter=how+to+join+parts+using+constraints+in+inventor&maxItemsToReturn=9