Casting On within a row

Hi I am new to knitting, I have a pattern that says knit x amount of stitches then cast on 25 stitches and continue with remaining stitches in row but I am stuck on… Casting on in the middle of a row. How do you do this??
If someone can help me that would be great. To me casting on is what you do to start knitting something I’m not sure about the middle of the row bit

Thanks

without breaking the yarn, cast on an extra 25 stitches imediately after knittting the X stitches, using a method such as a knitted, cabled or backward loop cast on. Knitted or cabled are probably best as they are strongest.

Knitting On and Cable Cast On are two methods you could use.

You apparently need to add a section 25 stitches wide to your piece, perhaps a hood on a poncho or something like that? It sounds like you are doing a HUGE version of a buttonhole! I’d be curious to find out what pattern you are using.

Hope this helps!

MGM