Check out this video tutorial on how to streak an agar plate. What's an agar plate? Well, an agar plate is a sterile Petri dish that contains a growth medium (typically agar plus nutrients) used to culture microorganisms. Selective growth compounds may also be added to the media, such as antibiotics.
First, inoculate the plate, then sterilize the loop. Cool and make the first streak. Sterilize again and cool. Do this for all of your scientific endeavors.