So I read the first 5 books of the bible and I have to say, I found a lot alarming. I need some advice on how to deal with this. I fee as I read the bible I will come across strong crimes.
You should start with the New Testament, the gospels, and then the epistles. The gospels start with Matthew.
The entire point of the OT, was to teach us and point us to the New Testament, but really, it was to point us to Jesus Christ. Genesis 1 through Revelation close, all the scriptures between point us to Jesus in one way or another.
So if you start with the OT and read, you will be confused because your understanding will be like a Jew of 300 BC, and yes, some Jews knew some things, but those are the ones who spent hours and hours studying the Torah to learn what God truly meant in them with the mysteries he hid in scripture.
So yes, you can learn the New Testament from inside the Old Testament, but you should expect to spend some 10 + years learning it that way.
For example, when genocide is enacted in the Old Testament, that genocide has to be seen through the lens of judgement of God brought through the hands of the Israelites. Saul was commanded to kill an entire people, but Saul did not and disobeyed God.
Yet the same law which condemned all those people in the eyes of God, also condemned all the Jews in the eyes of God. At one point in Judges, there is a bad crime in a Jewish town. So the Jews realize the problem, and according to what the law would prescribe as punishment, everyone in that village is killed, man, woman and child.
The Mosaic law's purpose was to point us to Christ, and in doing so, it condemns all men to death, man, woman and child. Curses to the 3rd and 4th generation for the sins of the parents, death and destruction all the days of our life. But on the cross, Christ has taken the curse, and taken the death prescribed by the law, justifying all men who receive him, justifying them by the law which previously condemned them, through his death, so we live according to greater laws, such as the law of faith and the law of love.
When you go back to the OT, you realize then a lot of the issues. For example, one reason you would have to kill whole populations is because the demons they had invited into their lives could not be eliminated. Those demons would visit their children to the 3rd and 4th generation, continuing sin and iniquity in the world. Christ's power had not come, so men would be bound by demonic powers they could not be free of. The only freedom available for those who did not sin, was to eliminate those who had by God's law which condemned all men.
That said, in the OT, they did not have to judge according to the law, if they knew something greater than the law... that would be faith:
Although most of the many people who came from Ephraim, Manasseh, Issachar and Zebulun had not purified themselves, yet they ate the Passover, contrary to what was written. But Hezekiah prayed for them, saying, "May the LORD, who is good, pardon everyone who sets their heart on seeking God--the LORD, the God of their ancestors--even if they are not clean according to the rules of the sanctuary." And the LORD heard Hezekiah and healed the people. - 2 Chronicles 30
So we are to learn from people in the OT, but we are not to follow their example, unless they are operating as King Hezekiah did in this passage, where he recognized they had been disobedient to God's law which would bring judgement upon them, and in this recognition, they have faith that God is greater than their failures.