Duel JoyStick from scratch

Hello, I'm relatively new to coding still but I do understand a decent amount. I'm currently attempting mobile development and I've run into a problem as I obviously cannot use my PC user input script due to the loss of a mouse and keyboard. And every time I search online for help a lot of people use pre-made assets from the asset store. I would really prefer doing this from scratch rather than use something others made. if anyone can help point me in the right direction it would be greatly appreciated.

I also looked at the learn center for mobile development. It wasn't really any help as the person in the Live Training I saw didn't understand people who were asking the question of duel joysticks