This is a bit of a trick: you aren’t going directly from a tubular cast on to a 2/2 rib; you are making a tubular cast on for a 1/1 rib, then rapidly using twist stitches to switch to a 2/2 rib. Since the knit stitches stay knit stitches, and the purl stitches stay purl stitches, it looks as though you have cast on directly to a 2/2 rib.
For Cast on, I mean use the Tubular Cast on.
Row 1 (RS): Cast on a multiple of 4 sts, using the waste yarn provisional cast on method, turn.
Rows 2 – 3: (Sl, p) across, turn.
Row 4: (K, 1/1 RPC, p) across, turn.
Rows 5 – 6: (K2, p2) across, turn.
Round 1: Cast on a multiple of 4 sts, using the waste yarn provisional cast on method.
Round 2: (K, sl wyif) around.
Round 3: (Sl, p) around.
Round 4: (K, 1/1 RPC, p) around.
Rounds 5 – 6: (K2, p2) around.
If none of this fits your brain, fear not, there are many other tutorials out there, here are two that I liked: