How to set cell in cels on different layers

[233thzhang]

I had a problem when I was drawing the layout, I wanted to place the grating coupler and the waveguide device in different layers so that I could have flexibility in picking the accuracy when fabricating.
However, I tried to put the grating coupler and waveguide devices in different cells, but only one cell will be shown in the final layout, I don't know how to solve the problem, thanks.