Once demolition has been completed, that is alot of paper work to be completed prior to a building permit being issued.
The next activity you will see on site is the laying out of the slab. The plumber is the first trade on site, trenches are dug and services laid. These trenches are inspected build the building surveyor and filled in leaving the rises in place.

The concreter then lays out the pods for the slab. Once the slab lay out has been completed, the building surveyor will inspect them and the concreters lays out the steel for the final inspection before the slab is poured.

While this is going on the electrician are also on site to install conduits to the slab to allow for the mains power to be installed at a later time.