Need help understanding directions

I am drawing a complete blank and was wondering if someone could help me or explain this to me. The pattern that I am doing is a hooded poncho for a toddler but there is one spot that I just can’t understand. I am the type of person to make things harder than they need to be so that is more than likely what I am doing but I just can’t get this. If some one could tell me what this means and how many rows I am suppose to do I would appreciate it. Thanks.

[COLOR=“Magenta”]Continue to work each side at same time with separate balls of yarn, keeping 4 sts at each side edge in Garter st. Dec 1 st at each neck edge every other row twice - 18 (20, 24) sts each side.
Work even for 3 rows. [/COLOR]

The first sentence I understand it is the rest that gets me confused. So how many rows do I end up with? This is the pattern I am trying to do-

Thank you very much

From what I understand, you’ll Dec over 4 rows (every other row twice), then even for 3 rows.