How do i dilute hydrogen peroxide 50%?

I don't know what dilute means and idk what the 50% is either. I usually just pour some peroxide into the cap until its full and then put some water in a cup and gargle both at the same time. Please don't tell me not to use it because I have read over articles and questions and it seems that peroxide is better in my opinion or give me an all home remedies website.