I decided on 8 flip flops but I am stuck on making sure that the doesn’t show up on multiple floors."I have no idea where or how to even start."
You can't really start until you decide how to represent the elevator. With 8 floors you could use a 3-bit up-down counter or an 8-stage bi-directional shift register (3 flip-flops vs 8 flip-flops). However, fewer flip-flops would require more decoder logic. Yet more flip-flops would require more careful design to not have the elevator be on multiple floors at the same time.
Maybe all that is necessary is a reset button to set the initial state of the state machine, and then make sure that during operation a floor (flip-flop) can only acquire the elevator (value of 1?) from an adjacent floor.I am stuck on making sure that the doesn’t show up on multiple floors.