Help me with this crochet pattern?

dec means decrease and you decrease your stitches every fourth, third and second stitch, according to your instructions. Inc means increase your stitch every other, 3rd and 4th stitch. I don't know what stitches are called for so can't explain how to do the decreases. Most pattern books and booklets have diagrams showing how to do those stitches. For your increase, you just make two of the same stitch in the appropriate stitch of the previous row.