2x2 ribbing

To knit the 2/2 rib stitch, proceed as follows:

Cast on a number of stitches divisible by 4 + 2 (22 stitches for example).

1st ROW: 2 knit stitches, 2 purl stitches, 2 knit stitches, 2 purl stitches, 2 knit stitches and so on...

2nd ROW:2 purl stitches, 2 knit stitches, 2 purl stitches, 2 knit stitches, 2 purl stitches and so on...

Always repeat these 2 rows.

Generally speaking for the rib stitch, the first number corresponds to the knit stitches and the second number corresponds to the purl stitches, on the work site.
For example, "2/1 ribbing": 2 knit stitches, 1 purl stitch.