I notice you have been playing less than a year so I figure its ok to send you to what's called a beginners lesson on this site.
Go to
True beginner? Here's a lesson for you!
and there are 3 lessons dealing with strumming this tune. Kirk shows you one way to strum it. If you then listen carefully to a few other examples from CDs etc you will be able to hear what they are doing. And also, any way that sounds good to you is probably the best way to go in the end.
One good thing about music is that when it hits you, you feel no pain - Bob Marley