I have followed this thread and looked at the pdf plans, like Chris E I am not sure a beginner could build a springer from them.
First off let me say they are a very good start at springer plans, and I am sure with a small amount of alteration they will be an asset to anyone building a springer for the first time, but to me they lack basic dimensions.
There are no material thickness dimensions or any notes to say what the material should be, either for the side, ends or the bottom. There is no indication that there should be a deduction from the front and back parts to compensate for the side material.
There are not enough measuring points to get the curve the correct shape, and all the dimensions need to be rounded up, as an engineer I can work steel to that kind of tolerance, but wood, nah!! If you look at the A4 plans Martin posted you can see that to get the curve there are measurements every 25mm
I am not sure you would need to say how to attach the materials together, I would have thought that was obvious