The Armbands here should easily print right from your home computer.  Right-click and save the page to your desktop, then right click to print.  It should automatically print out in Landscape format.  If it prints the wrong way, go to File/Print Setup (or Page Setup) and set your printer manually to print in Landscape mode.

After printing, trim into strips along the white space and wear it using a piece of clear tape to join the ends.

Give some to your friends and have everyone wear them to school the same day to help get the attention of others who will want to join you.