What can I use small bins/containers for in the cage?
Like the ones with holes and such.
Toy bins?
And how to do so safely?

I found some at a thrift store and got them because a video I saw said they were good to get
So I don’t know anything

Depends on size of holes/slots. Whether or not they have handles and size of that hole. Also how rigid it is. It should be able to hold a glider and toys whether it's sitting on the floor of cage or zip tied to side. Long flimsy slots can trap a leg or arm. All rules in your other threads apply.

Hope that helps.