Improvements to neural network?

Question

I recently created a neural network from scratch in Python, and I was wondering how I could add a hidden layer to it. Does anyone have any ideas?
https://code.sololearn.com/cG6V5OnH4HRc/?ref=app

Answer 1

https://stats.stackexchange.com/questions/63152/what-does-the-hidden-layer-in-a-neural-network-compute#63163

Answer 2

Thank you!