Php Joomla Basics

I want to learn php joomla from the beginning. So can anyone please help me.
thank you.

Are you asking about PHP in general, how to use Joomla, or how to develop themes/plugins for Joomla?

actually i am very new to joomla thats why i need basics of how to work with joomla and developing the remaining things in joomla as well.
thank you