A flat green mat ruled in metres, a mile and a half from anywhere anyone lives, where prims and stone cost nothing and nobody owns the ground. It is always daylight there, and no horses wander across it. Get there from the menu under Build, or from the build palette itself.
Two ways back: Back where I was returns you to the spot you left from, and Go to my home takes you to the home you have made at an inn.
Shaping a building out of prims is slow, fiddly work that wants twenty tries. Doing it on your own parcel means paying for every try and living with the wreckage of the ones that did not work. The workshop is where the first draft happens.
Your bench
The platform is divided into sixteen benches, and one of them is yours — the same one every visit, so your work is where you left it. You arrive standing on it. The dark lines ruled across the floor show where it ends, and that line matters: it is exactly where a blueprint stops. The finer grid between them is a metre a square, so you can see what the snapping is snapping to.
Sweep my bench clears your own plot. It asks twice, and it is not undoable.