Since there weren't details provided, I'm gonna assume I know what you mean and try to explain.
So you probably have 4 or 5 things lined up side by side that you want to layer, and those things are probably multiple pixels wide.
You'll want to use the PROP tool, set to X, and set the value to something like 100. Only use this tool on the leftmost part of each object. Then, set the value to 101, and do the same to what is now the leftmost part of each object. Add 1 to the value, move the next line, repeat, until you're finished with the whole object.
The !set x all command works fine for layering single pixels or lines, but if you want to layer 2D objects, you need to use the PROP tool.
Good luck!