Help to understand pattern

I am knitting a small dinosaur from Jean Greenhowes toy collection and the pattern goes

cast on 18 sts st-st 2 rows (done)

[B]Shape body[/B]
continue in st-st and inc 1 st at each end of next and every following alternate row until there are 30 sts.

now i understand that i have to increase by 1 st at both ends of every other row, but do i inc in the first and last stitches? i have always knitted the first st, then inc, and inc in the second to last st and knitted the last stitch - i hope you can understand that?

Claire

You could do it either way. If you’re seaming the edges, it might be better to do the increase a stitch or two in.