Hi, here is a nice and pretty explained video by learningconstruction.com on how to form a concrete slab. Forming a concrete slab you should keep these things in mind.
Learn what the major points and things we should remember during forming a concrete slab. In this video a General contractor is explaining his onsite experience showing how to form a concrete slab.
Hubs and reference points are the stakes used to mark the corners of the Building. On a large project, is typical that a surveyor is used to place these corner stakes so the building is placed in the correct location.