How can I add a USB port to my router?

Question

I want to add a USB female adapter to my Xiaomi 4c router. It has 5V, 1 ampere input. I did some research on it. They say that I need to add a 15k ohm resistor to it.

Here's the circuit diagram for USB:

It needs a 3.3V input. Where can I find a 3.3V input for it?

Here is the Xiaomi 4c router board:

I found these pictures on OpenWRT forum but I don't understand much.