How to get someone to the good path who is not leading a good way of life? If i want to get someone to the good path, who is not leading a good way of life, what should I do and where should I begin?

Many of my friends do not have much understanding of life and they often make so many mistakes. As I have learned about the consequences of untamed words and actions, I fear for them and I want to know how to get them to listen and think about their own stupid actions.

Are there any Theravada teachings on this matter? And/or do you have other advice (all answers are welcome and I am happy to learn every perspective)?
The only way to influence others' behavior is through example. Your question presupposes that your friends have a desire to change.  Not everyone wants to change, or wants your help in modifying their behavior. You might consider expanding your friendship base (i.e., find new friends) if your current friends' behavior is not to your liking.  We cannot assert ourselves or our beliefs onto others.  We can only influence by example.