These are all basic open chords that you should already be familiar with. The only chord that you may have trouble with at first is the B7 Chord as three of your fingers need to be on the second fret in order to play this chord. It can be kind of tricky, especially if you have large fingers.
Here is the Strumming Pattern used in this chord progression (where D= Down and U= Up): DDD DUU UDUDU
If this strumming pattern is too difficult, you can try something a little easier like a simple Down Up Down Up, but do try and challenge yourself.
This is very important. Do not try to rush through this chord progression. Make certain you play it very slowly at first until you are able to make your chord changes without error. If you rush through this, your chord changes will be sloppy and you will be creating habits that will be difficult to break.
Marty will also show you some really cool embellishments that you can add to this chord progression. I hope you enjoy and rock on!