All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
As for your second question, which is about the trials that occurred after the death of the Prophet, sallallaahu ‘alayhi wa sallam, the people of Ahlus-Sunnah Wal-Jamaa'ah wrote about it and recorded the authentic news of it, and said as Allaah The Almighty ordered them (what means): {Our Lord! Forgive us and our brethren who have preceded us in faith, and put not in our hearts any hatred against those who have believed. Our Lord! You are indeed full of kindness, Most Merciful.}[Quran, 59:10] The enemies of Islam and the innovators who hated the Companions of Prophet, sallallaahu ‘alayhi wa sallam, wrote about it as well, and they related fabricated and weak narrations, lies and falsities in their works.
We advise the questioner to read the books of Ahlus-Sunnah wal-Jamaa'ah written about this matter.
We also remind the questioner that he has to go back to the correct books of creed (Aqeedah), like Al-‘Aqeedah Al-Waasitiyyah, written by Ibn Taymiyyah and Al-‘Aqeedah Al-Tahawiyyah with its interpretation by Ibn Abu Al-'Izz Al-Hanafi in order to learn the correct creed of the Companions of the Prophet, sallallaahu ‘alayhi wa sallam.
There are many authentic books but they are in Arabic, for example: Al-‘Awaasim min Al-Qawaasim, written by Ibn Al-‘Arabi and Muntaqa Al-I’tidaal, written by Imaam Ath-Thahabi .
Allaah Knows best.