Preparation for bdpho

Thanks for reading this post. I want to attend bdpho next year but this is my first time attending an Olympiad. Which is why I am becoming frustrated about how and from where I should start my preparations, what should i read or how much time i need to become a master in solving problems. I need basic to advanced guidelines. I would be so grateful if any of you help me with this.

You can search it in YouTube.