Theme development from scratch

Hi, I am a new web developer in wordpress. I like to learn about the whole advance level of theme developing. Now I can make a basic wordpress theme with some php files like index.php, page.php, header.php, footer.php, single.php ect. but I wanna learn about more theme development like adding more theme options like adding Slider, adding Carousel, adding Portfolio adding Procass Bar. Which user can change theme from Theme Options or from Customize. From Where should I start to learn any tube channel or tutorial website.
Please help me someone.