Custom HTML Forms and Functions

Good Day WordPress users,

I don’t know if this is the right place to post this inquiry. Btw, I was tasked by my manager to create a web application and required me to use wordpress instead of the usual hard coded way I’m used to (because my manager wants me to learn developing in wordpress). I would like to ask some questions about wordpress.

1.) How do I create custom input fields? (e.g. Game Name, Genre, Total Online Users)
2.) How do I add functions to those fields in order for it to be inserted into a custom table in my database?
3.) How do I make a login page as my front page? especially for those user that weren’t logged in.

I’m a complete noob about wordpress and other CMS but I can do this with PHP and HTML alone. Hehe. Please help me. Thanks Everyone! 🙂