You need to change the right needle to your left hand. The instructions you gave sound as if it's for a knitted cast on. After you do your cast on of 4 sts, put the needle back into your right hand and continue on across the row as instructed. Either there is a typo or I'm not adding right (entirely possible, even likely, or I'm just missing something) because starting out with 30 I come out with 38 sts to end the row, not 48.
Cheating is an option. . . . Cheaters never win and winners never cheat, but smart knitters who want to retain an iota of sanity do, cheerfully. ~~Kory Stamper