Thank you for sharing the screenshot. You can use the Structure Group in Lumerical to build a supercell with multiple number of elements. You can refer to the following article for more information and an example:
If the arrangement of supercells is periodic and extends infinitely, then you can build one structure group and simulate the single supercell with Bloch/Periodic boundary conditions.
If you want to simulate the entire structure with a definite number of these supercells then you can either create multiple structure groups and position them at the desired location or create nested structure groups.
Please let me know if this wasn’t clear or if you need more information.