I want to create two validation lists

1 st list showing the shelf no.

2 nd list showing the empty slot number of the picked shelf.

Information:

1 products on the shelf can consume 1 or more shelf slot within the same shelf.
I will merge and center the the cells if this is the case.

Can you please check the examples i uploaded?

How can I do that?

Thank you so much!ShelfExample.xlsx