For the fourth, and hopefully last time...
This is after the old threshold was removed. The piece of wood that stuck to the glue was the top little strip at the left edge of the photo. Fortunately, it wasn't damaged when the old threshold was removed and the floor guy was able to stick it back together after I thoroughly vacuumed out the joint. He applied a little wood glue (in the yellow bottle) to help it stick.
As a precaution in case the construction adhesive does ooze out and stick to the floor boards, I suggested that we wrap some doubled-up wax paper around the floor board. This photo was taken after I had done that. The little bit of masking tape is to hold the wax paper in place.
The next step is to apply the construction adhesive.
And then to put some weights on top of the threshold to hold it in place until the glue sets. And also we have to hold our breath until we can take the weights off.
Previously we left the weights on for 24 hrs, but the guy said 8 hours. I took the weights off after 8 hrs and I could move the thresholds so I put the weights back on.