There are different ways to do Bar bending schedule for slabs. Mainly that depends on whether it is a one way or two way slab.
Based on the GFC structural drawings and shapes of the steel bars given by structural consultants we can calculate steel for slabs.
The major difference between one way and two way slab is in two slabs there will be a top reinforcement at all edges of the slab and projecting length of the bar as per the design given by the consultant. For one way slab it is similar except only bottom reinforcement will be applicable
I am attaching some example for slab steel BBS calculations. I hope this will helps you.