Increasing more than one

Please-My instructions say cast on 12 stitches at the beginnig of next two rows.how do I do this ?

Hi and welcome to Knitting Help!
Take the needle with stitches on it in your left hand and do a knitted or cable cast on of twelve stitches. Knit across the newly cast on sts and the sts that were on the needle to start. Transfer the needle with the sts from your right to your left hand again and cast on another twelve sts and then work across all the sts. There you have it.