Would someone please crochet up a swatch section to see if they can
follow these instructions. It's a baby blanket 40 x 60 which calls for
ch 150 to begin with. It's the 2nd row which is troublesome.
Instructionsare for colors A,B, and C so it has a checkerboard look to
Row 1 (right side): with CA, SC in 2nd ch from hook, *dc in next 3
ch**, ch 3, skip next 3 ch; rep from * to last ch, end at **; sc in last
ch; turn--149 sts.
Row 2: With color CB, ch 1, sc in first sc, * ch 3, skip next 3
dc**, working over ch-3 of last row, dc in next 3 ch of beg ch; rep from
* to last sc, end at **, sc in last sc; turn.
What you are doing in row 2 is working a double crochet in each of the 3 skipped chains of the foundation row. When you complete the second row you will see alternating color groups of 3 double crochet. Doing the rows this way interlocks the rows. The ch 3 spaces of row 1 will be inside the double crochets of Row 2 because you are not working stitches in them, but rather in the row below them (that's what they mean by working OVER the ch 3 in Row 1).
Hope this helps. If you still have problems, contact me at email@example.com and I'll see if I can explain it in better terms.