I diligently measured the bed boards already in the garden and determined my lumber needs. I then randomly poked around the garage and found I already had all the materials. (Main board courtesy of my previous owners.) I went to it.
Tom Wilson, Shelby's dad, is the one who helped me build the deck and taught me what I know about working with wood. Tom had two favorite things, as far as I could tell: his Sawzall and "cutting a notch out of it." So when I got to the point of installing a side board but almost running into the fencepost, I employed the second of this favorite things.
I measured, I cut, I drilled, and by golly I got the thing in! It only took about 2 hours, and probably would have taken a skilled person about 25 mins, but I did it...
It's all ready to plant my perennial asparagus bed, which I did a few weekends later (last weekend). Check back in 2 years to see how it tastes!