Connecting AVR Microcontroller to USB

I am working with an [ATmega328. What I want to do is finding a way to save any value in any GPR of the microcontroller using the PC.

I found [this video where an already made interface is shown. Apparently, that is very user-friendly. But does it what I’m trying to achieve? For example, if I want to save the value 0x3B in register R16, could I use that software to do it via USB?

Also, I don’t know how to connect the USB with the microcontroller pins. I’ve found this image

but I would have expected the pins TXD and RXD to be used. Is this connection alright?

Sorry if the question is a bit messy, I’m a beginner with this stuff. If you need any further information please let me know.](](

The micro is undoubtedly running VUSB firmware, which is open source. You will have to modify the basic software interface to do what you want.