How to fix graphene sheet position in a nanocomposite amorphous cell

Hi everyone

Recently, I started to use amorphous cell module and construct a nanocomposite cell.

I tried to make a cell with graphene sheet and polymer but I can't fix the position of garaphene in the cell (for example in the middle, top or bottom of cell)

Could someone help me it's possible or not?

If it's possible how I can do that?

Regards.