New member with how-to question for shaping a slit in a tunic sweater

Hi all,
I just joined this website and was pleased to find it. I recently started knitting again and am making a sweater with side slits at the bottom. It has a box pattern which is easy enough. However, after knitting about 43 rows in pattern, the instructions say to cast on 5 stitches and then continue in pattern for the rest of the row. The next row has me cast on an additional 5 stitches and then continue in pattern , incorporating that pattern into the set of 5 cast-ons from the previous row. After that, the pattern is straightforward. I don’t know if I am not casting on properly, but when I added the 5 stitches in the beginning, my yarn wasn’t in position to start knitting in pattern – the yarn was at the end of the 5th cast-on and therefore 5 stitches away from the original knit stitch. The back will be worked the same way as this front. I’m not sure if I’ve explained my quetsion clearly but the bottom line is, how do I account for the slit at each side? I’d appreciate any help you can give me. Thanks.

You CO alright, you just have to knit those 5 sts in pattern too at the beginning of the row.

Thanks – that’s what I did but I didn’t want to go too far if I was wrong?