Flip your folded paper over so that you're looking at the back. Then, cut off the top of the paper at an angle. Make sure to cut if off so that all remaining layers of paper are equal. As you can see, I'm basically cutting off all of those excess blue edges.
Cutting at an angle is what makes the points of the snowflake. Eventually, you'll learn to cut at different angles to make snowflakes with points that are more or less sharp.
BONUS: The extra image shown in this step is from a worksheet I made for a class, which just re-explains steps 4-6 for those who may have a harder time visualizing the "fold in thirds" part. If you've already got the hang of it, just ignore the second picture and continue on to step 7.