Step 1 place a rare block(a block that is NOT in your world like brick cause if you place dirt or any common block, you’re gonna have a hard time or you must be a pro)and place sand/gravel on top of it

Step 2 EXIT YOUR WORLD

Step 3 open PocketInvEditor Pro

Step 4 find your world and go to edit terrain

Step 5 tap “Select whole world” first then tap replace blocks

Step 6 tap on the first browse then find brick block then on the second browse tap Air

Step 7 tap OK then wait till it says something like changed

Step 8 go back to your world

That’s it!

Warning if you block update the sand/gravel in any way, it will fall