New Knitter fleck stich advise

Hi, I’m a new knitter. I’ve made about 800 scarves. I was trying to branch out by making my sister this fleck stich purse. The patern is:
Row one: knit
Row two: purl
Row three: knit one purl one knit one purl one…
Row four: purl

Row one I’m aces. Row two ain’t bad. Row three, I have a little mantra that helps me keep the knitting and purling separated, but then when I go to purl Row four, I can’t tell where I’m supposed to be starting.

I’m thinking perhaps my work is too tight. Or…
Any help would be greatly appreciated (by myself and my family, they’ve asked that I stop making them scarves).

Purling the knit sts is going to seem a little strange but just keep going into the stitch from right to left (and maybe slightly from the back) as if it were the usual purl and it’ll be fine. It may help to look at the purl st video on this website under the Free Videos tab, the purl stitch. Practice will help.
Wow, 800 is impressive!