I am thinking to prepare a new course: Learn to Design Your Own AVR Boards
After this course, you will know how to design your own Arduino board.
During the course, you will use Arduino Uno reference schematic, you will learn how to modify it and how to do PCB layout. The course videos are step-by-step, just follow them and design your own boards.
This course is perfect for hobbyists and beginners.
Please if you would be interested, fill up this form