Casting on Help

I have knitted 20 rows and for the next row am to cast on 10 stitches then knit to the end of the row. I can’t wrap my brain around how to cast on to an already knitted piece. Do I just increase 10 stitches?

Use a knit cast on. At the beginning of the row, knit into the first st, but leave it on the needle, put the new st on the needle too and repeat until you have 10 more. You can’t inc that many in one spot, it’ll be all bunched up and ruffley. That’s why they say ‘cast on’ so the sts extend the row.

I now know which video to watch to see how to do this. I’m a visual learner and these videos are great when you know which one applies to what you are trying to do.