That is going to be an expensive piece of plate, going down to 1 inch would save a very big penny. Most shops can bend 1", but 2 inch takes a serious break (our 150 ton wimpers under 2"). Also 1 inch can be plasma cut with 260 machines, while 2" is torch only. Plasma is much cheaper.
To unfold a shape: draw a work path along the bend axis. ASTM 36 is close to 1/3 of the width on the inside of a bend. Have a fillet inside dimension from the break/press handy. (example uses 1/8"). Also take in account miters, extending the bend axis lines to square material. Add up all the lengths of the work path; your case has bottom, bend, and top. draw your base line, and then a line perpendicular with total work path length. draw top line, then your edges.
Simple, now repeat with multi-bends and complex shapes and your stomach will burn from coffee and aspirin.

then the original drawing is short a view. Not the first time, or last, I will mis-read a drawing. Unwrapping procedure stays the same.

For roughing out an unwrap use paper, you can even check for exactness by printing a copy with the bend line section then cutting out with scissors or xacto. Paper is cheap and soft.

print window has a scale function. print to numerical scale not paper size - this helps edits.