Yes, welcome to DD, KatInMa! So glad you're here with us.
Here's a link from the "Getting Started" section here at DD about how to load brushes in Photoshop. Maybe reading it will give you a better idea about what is meant by a brush and you can check your software for directions.
Like Brittany said, there are numerous ways to use brushes. Just a few examples: use them to edge photos or borders, to create a soft subtle background, to distress a paper or photo.
One thing you might do to help you learn what is meant by brush work is to go through the gallery and look at the credits listed for the layout to notice what brushes the person used to create the layout.
Here's just a few to get you started:
Sharon added a leaf motif:
At First - Digital Scrapbooking Ideas - DesignerDigitals
Kathie02 created a lovely background with subtle brushes.
dear mother nature - Digital Scrapbooking Ideas - DesignerDigitals
Steph used a brush to edge both sides of her photo:
Here & Now - Digital Scrapbooking Ideas - DesignerDigitals