Dear Brother As Salamu Alaikum I have some confusion regarding messengers of Allah (SWT). As I know before that, so many messenger came and the first one was Adam (AS) and the last one is Muhammad (S). But, recently I read in one Islamic book that first messenger was Nuh (AS). Then what was the position of Adam (AS). And can you inform me exactly how many messengers came and what are the names of all messengers.Thanking you.

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

Adam () was the first Prophet (Sallallahu Alaihi wa Sallam) and Messenger as clearly stated in the Holy Qur'an and he was required to practice the revealed Shari'a among his nation.
Allah says: {And He taught Adam all the names (of everything)….} [2:31]
Then, the story of the two sons of Adam indicates that they had shari'a.
Here, we state that the sound Hadith of al-Shafa'ah (intercession) that reads: "They will come to Noah and say: you are the first messenger on earth…", puts the inquirer in such confusion.
Having researched carefully, scholars said: 'Adam and Sheeth (Peace be upon them) were messengers and Prophets, before Noah (peace be upon him). But, Adam was sent to his children, who were not disbelievers and ordered them to follow Allah's orders. Then, Sheeth was Adam's successor. Noah was sent to disbelievers on earth'. This opinion is more correct than others.
In brief, Adam was the first Prophet and messenger on the earth.
Allah has sent a Prophet and messenger for each and every nation or earth, and He sent Muhammed (SAW) for the whole human being.
Allah says: {……And there never was a nation but a warner had passed among them.} [35:24]
{And verily, We have sent among every Ummah (community, nation) a Messenger (proclaiming):….. } [16:36]
{And We have not sent you (O Muhammad SAW) except as a giver of glad tidings and a warner to all mankind, ….} [34:28]
Then, the Prophet Muhammad (Sallallahu Alaihi wa Sallam) informed Muslims of the number of prophets and messengers those came before him. In al-Musnad from Abu Zar (RAA), who said: 'O Allah's Messenger! How many messengers came before?' The Prophet (Sallallahu Alaihi wa Sallam) said: "Three Hundred and fourteen."
In the narration of Abu Umamah from Abu Zar who said: 'O Allah's messenger! How many Prophet (Sallallahu Alaihi wa Sallam) were there? The Prophet (Sallallahu Alaihi wa Sallam) said: "One hundred and twenty four thousand, and there were three hundred and fifteen messengers from among them." AlBani said: 'It is a sound Hadith' .
In addition to that, the names of twenty five Prophets (Sallallahu Alaihi wa Sallam), and messengers are mentioned in the Holy Qur'an, eighteen ones mentioned in al-An'aam Surah. The other prophets and messengers are Adam, Hood, Saleh, Shu'aib, Idrees, Zulkiff, and Muhammad (Peace be upon them all).
Allah says: {Allâh chose Adam, Nûh (Noah), …..} [3:33] {And to 'Ad (people We sent) their brother Hûd…} [11:50]
{And to Thamûd (people, We sent) their brother Sâlih (Saleh).….} [11:61]{ And to the Madyan (Midian) people (We sent) their brother Shu'aib. …..} [11:84]
{And (remember) Isma'îl (Ishmael), and Idris (Enoch) and Dhul-Kifl (Isaiah),} [21:85]
In al-Ana'm Surah: { And that was Our Proof which We gave Ibrâhim (Abraham) against his people. We raise whom We will in degrees. Certainly your Lord is AllWise, AllKnowing.{} And We bestowed upon him Ishâque (Isaac) and Ya'qûb (Jacob), each of them We guided, and before him, We guided Nûh (Noah), and among his progeny Dawûd (David), Sulaimân (Solomon), Ayub (Job), Yûsuf (Joseph), Mûsa (Moses), and Hârûn (Aaron). Thus do We reward the gooddoers. And Zakariyâ (Zachariya), and Yahya (John) and 'Iesa (Jesus) and Iliyâs (Elias), each one of them was of the righteous. And Ismâ'il (Ishmael) and Al-Yas'â (Elisha), and Yûnus (Jonah) and Lout (Lot), and each one of them We preferred above the 'Alamîn (mankind and jinns) (of their times).} [6:83-86]
Hood, Saleh, Shu'aib and Muhammad were from Arabs as recorded in Ibn Hibban's Sahih from Abu Zar.
Also, according to Ibn Kathir, there were other prophets whose names mentioned in the Sunnah (not in the Qur'an) and Sheeth was one of them and he received Fifty scrolls from Allah as revelation.
Furthermore, in Sahih Muslim from Abu Hurairah (RAA) that Allah's messenger (SAW) said: "One of the Prophet (Sallallahu Alaihi wa Sallam) was on a Ghazwa (a battle for the sake Allah) .. and he said to the sun: "Both of us are doing by Allah's orders. O Allah! Hold it back sometime for me." We can deduce that the above mentioned Prophet was Yusha Ibn Noon while he was on his way to Jerusalam." [ Ahmad ]
There is disagreement about Zul-Qarnain, Tubb'a and al-Khidr, who are mentioned in the Qur'an, if they are prophets or not.
Some scholars believe that Zul-Qarnain and Tubb'a prophets. But, it is safer to avoid such opinion for the prophetic Hadith recorded by al-Hakim with a sound chain reads: 'I do not know if Tubb'a was Prophet or not. I do not know if Zul-Qarnain was a Prophet (Sallallahu Alaihi wa Sallam) or not !' . Al-Kidr, according to the dominant opinion, was a Prophet.
Allah says: { ……..And I did it not of my own accord….. } [18:82]
This verse means that al-Khidr received revelation.
Allah knows best.