OK, this is the best way I can explain:
Usually the turning chain counst as a stitch, so if you do a stitch in what is the top of the last dc in the previous row, you are doing 2 stitches in it, since you count the turning chain as a stitch. So your afghan grows one stitch each row.
Usually if doing a dc block, you chain 3, turn, skip a stitch then dc in next stitch. It is like counting back from your hook on the starting chain, you have the turning chains (1st-2nd-3rd) a skipped stitch (4th), so you crochet in the 5th loop from the hook.
If doing a hdc, it is only 4 back as the turning chain is usually 2.
If doing a tr, it is 6 back as the turning chain is usually 4.
This pattern has two hdc stitches on either side of the pattern, the first one of each row will be a turning chain.
Do a small practice piece, chain 18, follow the pattern instructions, row 1 will have 16 dc. Then follow the directions for rows 2-5, or do rows until you are comfortable with the turning chains & border. I think once you get a couple rows in you will have the hang of it. This pattern you will always be doing fpdc and bpdc onto a either a fpdc or bpdc (they just alternate directions) and the border hdc onto another hdc.
Better to practice on a small piece & make sure you get control of the counting & the pattern than have to rip out 170+ stitches.
If you get the first 2-3 rows right, you will be fine the rest of the way up.
