Please help me codding

Hello friends

I am new and i recently start learning the wordpress theme design
i cover up the index. single. post . sidebar but i am not understand the
coding of comments .php , i think it is a high level codding
well i want to know the best way to learn all about the wordpress theme
What i learn first is it necessary that i learn php first, i see the wordpress for designer series but i not understand the functions,tags and their use that where i can use it

So please help me , i want to learn make option pages , meta boxe and some features like today wordpress theme

I hope U help me