Is saying sana at the start of the prayer a must do

Every sunnah is important in salaah, because Allaah was most pleased with the salaah of Nabi -sAaws- and he ordered us: "Salluu kamaa ra-eitumuunii usallii!" Pray as you have seen me praying. And du`a al-istiftaaH is what he used to do according to many aHaadiith. I`ve heard not allways, but it was from an unreliable person, and he didn`t show his evidence. He may be correct, but I don`t know.
What is for sure is you should pray from your heart to Allaah, and be pleased that He sees you praying like His beloved Nabii -sAaws- prayed.

Every sunnah is important in salaah, because Allaah was most pleased with the salaah of Nabi -sAaws- and he ordered us: "Salluu kamaa ra-eitumuunii usallii!" Pray as you have seen me praying. And du`a al-istiftaaH is what he used to do according to many aHaadiith. I`ve heard not allways, but it was from an unreliable person, and he didn`t show his evidence. He may be correct, but I don`t know.
What is for sure is you should pray from your heart to Allaah, and be pleased that He sees you praying like His beloved Nabii -sAaws- prayed.