You pray them as 2 sunnah + 2 sunnah then 4 fard and then 2 Sunnah afterwards.
It is permissible to pray the sunnah as soon as you hear the athaan for dhur.

Im really confuse of the sunnah prayer for zuhr, 4 rakaat before zuhr? 2 unit x 2? Or 4 rakaat 1 salaah? And can i pray the sunnah (4 before zuhr) at the time when the adhan is done? Thank you shaykh