Hello
Decrease 1 stitch at end of next and 4 foll 12th rows.
So
Next row dec 1 stitch at the end of the row.
Then call the next row, row 1 and decrease on rows 12, 24, 36 and 48.
Work 7 rows.
“Work” means continue with whatever pattern you are using, stocking stitch or an established cable or lace pattern for instance. There are no decreases on this row (unless you were working an established pattern which uses them such as lace made with increases and decreases).
Ending with a WS wrong side row means you work the wrong side and turn ready to work the right side with the next instruction.
Hope this helps