Hey everyone,
What I'm talking about is boom chick strumming, it's also known as root 5 strumming. Using the G chord you play the G note in the 3rd fret, on the 6th string, then strum the other strings. Then play the D note which is the open 4th string, and strum the other strings. Then keep repeating it, and when you feel comfortable move on to another chord.

There are many tutorials about this on the site, see what you can find on it. These are well known strumming patterns, used in several genres of music. It's the first strumming pattern I ever learned, and it will come in handy as you progress.

Since you're just now learning about boom chick strumming, we'll cover the forward roll a little later. I've been replying to this post, while winding down from last night's performance. I'll sign off now, and I hope this helps you.