If you want to print them larger than "normal" paper you have a couple of options.
One is to print at school. A GREAT option if you have a nice color copy machine. Check with your secretary or another teacher that seems pretty tech savy if you don't know how to change sizes! School copy machines are awesome for shrinking and enlarging papers! If everyone is struggling check with the maintenance person for your machine (Jen's Dad just retired from this job and he says they love it when customers ask questions - it ensures the customer uses the machine to it's fullest and is usually happier!).
For years we never had a color machine at school, so we relied on printing color papers from home. It's actually pretty easy to change the size of your copies using a printer at home!
To decrease the size or shrink a page keep the Size button selected and click on Custom Scale. From there decide how much you want to shrink it by. In this example the page has been shrunk to 50%.