How does the worshipper intend to perform the Dhuhr prayer?

The intention (niyyah) for prayer resides in the heart, and it is not prescribed to utter it verbally; indeed, verbalizing it is an innovation (bid'ah). It suffices for the Muslim to bring to mind in their heart the prayer they are about to perform (such as Dhuhr or Asr). If one is a follower (ma'mum), they should intend to follow their imam. There is no need to specify the number of rak'ahs or whether it is an obligatory (fard) or supererogatory (nafl) prayer, as these are implicitly known. The intention to follow the imam is a universally agreed-upon matter, and bringing it to mind is easy. Thus, whoever stands for prayer in a congregation with the intention of performing the prayer, this intention is sufficient for them.