You bind off 3 stitches at the beginning of each of the next two rows.
Edited to add: When you have completed the number of rows or inches required for the body and you are ready for the armholes, you will have 46 stitches on your needles. To shape the armholes:
Bind off 3 stitches, leaving 43, and knit (or work in pattern) to the end of the row. Turn.
Bind off 3 stitches, leaving 40, and work in pattern to the end of the row. Turn.
Bind off 3 stitches (the second time at this edge), leaving 37, and work in pattern to the end of the row. Turn.
Bind off 3 stitches (the second time at this edge), leaving 34 stitches, and work in pattern to the end of the row.
The instruction doesn't mean to bind the stitches off twice, it means to follow the direction twice to bind off 3 stitches at each armhole edge (4 bind-off actions in all).