Bible contains the necessary knowledge for humans. Bible, being the word inspired by God, is the main book of Christians and is the one they should all read.
So the order of reading would be:
1) Matthew
2) Mark
3) Luke
4) John
These 4 are stories about the life of Jesus. Very important to read them. They are found at the beginning of the New Testament. If you have only little time to read, I suggest you read Matthew, Mark, Luke and John. These are the most important parts of the Bible.
5) Acts
Acts are deeds done by the disciples of Jesus.
Next, you should be reading:
6) Genesis
7) Exodus
8) Leviticus
9) Numbers
10) Deuteronomy
These contain the story of first humans and first believers.
If you like the praises of God and poems, I recommend Psalms in the Bible.
If you like traditional wisdom, I recommend proverbs - there is chapter in the Bible called proverbs.
If you like love stories, Bible has that too in the chapter Song of songs.
If you have any particular question in life but you are too lazy to read the entire Bible, just go to google and type "What does the Bible say about this". After finding what chapter in the Bible relates to your problem, open the Bible and read it.
Dont forget about prayer. After reading the Bible, say the prayer. When going to bed, before falling asleep say the prayer:
Our Father in heaven,
hallowed be your name,
your kingdom come,
your will be done,
on earth as it is in heaven.
Give us today our daily bread.
And forgive us our debts,
as we also have forgiven our debtors.
And lead us not into temptation,
but deliver us from the evil one.