What do I do if I do not understand the Bible?
You do not have to interpret everything alone.
The Bible is the Word of God, but it is not always easy to understand. That is why the Church reads it with Tradition, the Magisterium, and an interpretation faithful to Christ.
There is nothing wrong with starting humbly: a Gospel, a good guide, the Catechism, or a reliable commentary. The Bible is not there to invent a private faith, but to listen to God within the Church.
The key is not to use doubt as an excuse to remain still. A question lived well can bring you closer to God if asked with humility, if it seeks truth, and if it is willing to change something when it finds light.
Key idea
The Bible is understood better with the guidance of the Church.
Your challenge for this idea
Read a difficult passage and look up a serious Catholic commentary before jumping to conclusions.