The legs have 1" of movement. In the photos you can see how they slide up and down.
The leg has a "T" nut attached inside it.
A section of threaded rod is inserted into the "t" nut. The hole below the t-nut is deep enough for the rod to descend just over an inch. In the above photo the rod is barely threaded into the t-nut.
A nut and a washer is positioned as shown above and is held in place with blue thread locker.
A washer and wing-nut are positioned as shown above and are also held with blue thread locker. The wing nut is tightened against the lower nut just enough to remove slack but allow it to turn easily.
Turning the wing nut causes the threaded rod to rotate and move the t-nut and leg up or down.
I used two straight "line levels" for leveling. I routed out a slot for the levels and glued them in place. A smaller viewing "slot" was cut in the top.
