You inc on BOTH ends of the row, so there's 2 incs per row. First inc row takes you from 38, to 40, then on the next one it's 42, and so on and you end up with 54 sts when you're done with the increases. When there's a 0 for your size, skip it and go on to the next instruction. 'Cont straight' means just that - no more incs, work on the sts you have in the stitch pattern. You've got it pretty well figured out I think, just remember to inc at the beg and end of the row.
sue- knitting heretic