I use a cheap online app called SmartDraw that you can draw scaled floor plans. I then took my sketches to a designer that made the floor plan "blueprints" for me and he made sure I had considered all my dimensions correctly for standard needs. Then we had our metal building designed by the custom building fabricator and he used my floor plan blueprint to design around.
I attached my final floor plan we used for our build.
I managed all of the construction, but subbed everything out. The detached garage was an addition around in late 2018. The house was built in 2011. Just the house, not considering septic or anything else was $100k or $50 sq ft. The interior living space is 2,000 sq ft and the foundation with porch and patio included (total area under roof) is 2,682 sq ft. I would guess into today's dollars, if I did the exact same construction, it would be $140k or about $70 sq ft.