[ Guidance Needed ] How to make my own Arduino. (for USB com)

[polymorph]

I think because you edited your first post, it made what followed nonsensical.

The Arduino is open source, so you can look up the schematics here:

Arduino Hardware

The other person posted this link to an Arduino on a breadboard, which shows what I was talking before:

Building an Arduino on a Breadboard | Arduino Documentation

However, that is incomplete. There should be three 0.1uF capacitors added. One each from Pin 7 (Vcc) to ground, Pin 21 (ARef) to ground, and Pin 20 (AVcc) to ground.