Actually, field stripping the Woodsman is pretty easy and even detail stripping is not that hard, IF (and it is a big IF) you locked the recoil spring before taking the back strap off. If not, you have a problem.
Just in case that is what happened, here's how to fix it.
Hold the slide upside down in a padded (leather is good) vise.
With a small screwdriver, push forward on the recoil spring guide until the guide clears the lock (the little finger shaped spring). Now feel underneath the slide and push up on the little checkered button. That will push the lock up on the inside of the slide. Now let the spring guide go easy until the lock engages in the lower (top in normal position) part of the groove in the guide.
Now put on the slide, and insert the backstrap which is also the slide retainer. When it is in place, pull the slide back to disengage the lock and release the recoil spring.
Jim