Purchase the load center and ground bar below:

Purchase the QO load center QO2L30S series below:

https://www.amazon.com/gp/product/B00...

Purchase Ground Bar comes separately from load center PK3GTA1:

https://www.amazon.com/gp/product/B00...

I am not a professional nor do i claim to be but this is how i wired my 30 amp sub panel. I hope it helps anyone who was just curious to understand. Feel free to ask me any questions as I may be able to help you save some some money!