how to change the xbox build....

Tried both DNS with restart no change in issue. I'm not sure on the build part don't know how to check that

sand scaffolding is pretty much it. Either drop it from above and let it stack up to meet you so you can step down and lower yourself to see the underside, or start from the ground and stack up to be where you need to build under.

And of course, clean up the sand when you are done (which is pretty easy from the ground).

I use dirt blocks, easy to collect and easy to tear down once complete. You don't need as many as you do with sand either, seeing as sand drops when place in the air against another block. Dirt stays placed. You won't be able to go under a block though,
you have to build another platform from the ground up to be able to get there. You can crouch to keep from falling off the block while leaning over to place another block on the side as well.

Either build a tower of sand straight up underneath or set up a piston to push some blocks down.

ah well, great minds think alike.