Asking for help: Planning a door opening in a non-load-bearing wall.

Hello!

I have been working some months on converting a stand-alone building (small garage with attached "shed") to an office. I have been lucky enough to have guidance from a master electrician friend, my next door neighbors (one is an architect, the other on the other side is a commercial construction foreman), but i'm now stuck on visualizing what I need to do about a doorway I would like to insert.

The wall where it would go currently divides the garage and the "shed" building. Both of my neighbors looked at it and said it was non-load-bearing and I could easily insert a header and additional studs to frame the rough in for the door.

I have watched a number of youtube videos on the subject and I believe I understand that I will need a header (probably made with either 2x4 or 2x6 lumber sandwiching a 1/2" plywood strip to make 3.5" side length) and I will need jack and king studs?

I am still stuck on fundamentally understanding what those studs do and the configuration of the frame, including the header.

I have made this diagram to show the current measurements, once I remove a stud and make a place for the doorway. My neighbor said to make the doorway 6" away from the wall on the right. (it will be a left-handed, outward-swinging fiberglass door. 30 inches by 80 inches.

The grey beam in the middle is the stud I will remove.

(my diagram here)

My trouble is in visualizing the configuration of the wood and understanding how to assembled what I need to assemble. I'd like it to be done right and be as sturdy as possible.

Thanks for any help!