Shape shoulders?

the directions say cast off 7 sts at beg next row, and this is the part I’m not sure what to do: then beg foll alt row once. Can anyone help me in what exactlty to do on this step? Thanks so much!

The phrase ‘foll alt row’ means the 2nd row after. It means to BO on the next row, finish the row, turn and work back, then BO at the beg of the next row.

Thanks you so much!