Need help with shed bracing.

Hi, I am going to try and explain this the best I can, I have bracing questions on a shed I am building.

I have an out door pen, it is 20 ft long by 12 ft wide and 8 ft high.
It is built with 6x6 in corners and in the center of the 20 ft runs. I then have a 2x8 all around the bottom top and the middle, this had Weld wire in it for birds.

I now want to enclose it, so I put 4x4 on the bottom and I attached 2 and 9/16th inch thick by 6inch rough cut barn board flooring and I ran them the 12 foot width across.

I I am raising the one 2o ft long end up another two ft with a 2 ft fall I built to get the pitch for the metal roof. I cut in and attached rafters 16 on center for this and I put down 12 x 1 rough cut lumber down as perlins going all the way across every two ft.
The one 12 ft end Id like to open up and make 2 4 ft wide doors.
Outside of the building will be rough cut board and batton.

Any ideas on how I should brace this building, I normally would brace it diagonal on the ends but Id like to open the end up. Its a storage shed but obviously I want it safe

Building is not in concrete as I never planned to do this when i build the run. It is going to be attached to a 10X12 Shed on the one end which I over built and that thing is not moving, 2x6 framed 16 oc walls 5/8th plywood on the outside with board and batton over it, 1/2 plywood on the inside, 2x8 floors with plywood roof same as walls.

I know Pictures would be helpful I just dont have any handy. Thank you

I think it depends a bit on your anticipated wind load.  Hurricanes could change the options.

If you have a 12' end wall with two 4' doors in it, can you arrange it so that the doors are pushed to one side and you have a 4' section of wall on that end of the building?  That should be enough to make a good diagonal brace.  Failing that, centering the doors would still give a 2' wall on either side which would be a decent pair of braces.

Also, if the doors are a normal height, the angle brace can shoot over their corners on their way up to the upper cross beam.  So a 2' wall could maybe fit a 2.5" wide angle brace.  If I'm making any sense...

I got a 30 x 48 through barn framed 4 feet on center, and the sheathing around the doors on the end is more than enough to laterally brace the building.

I'm with Mike on this, except that I'd use plywood to make a shear panel(s) on the end with the doors rather than braces.
Doesn't matter if you do 2 feet on either side of the doors, or 4 feet on one side. I'd cover everything that wasn't the doorway, and nail off the plywood every 4 inches.
You could do this on the interior, and make the exterior B&B siding like the rest, or all exterior like your other shed. It will be very stiff.