Okay kiddo, let me tell you about Siddhar in a way you can understand. Siddhar is actually a name that means "one who achieves his goals." It's given to people who have accomplished something important in their lives.
But when people talk about Siddhar, they usually mean a specific person who lived a very long time ago in a place called India. This person's full name was Siddhartha Gautama, but people usually just call him Buddha.
Buddha was a prince who lived in a fancy palace with all the nice things a little prince could want. But even with all his riches, he still wasn't happy. He saw people suffering outside the palace walls and wanted to know why. So one day he decided to leave the palace and find the answer.
Buddha spent many years studying and meditating, trying to find a way to end suffering. And one day, he finally figured it out. He found a path that leads to inner peace and happiness, and he started teaching others about it.
That's why people call him Siddhar – because he achieved his goal of finding a way to end suffering. Today, many people still follow his teachings and try to live a peaceful and meaningful life.