There is a standard way of bar notation that should be followed according to the drawings. This notation indicates the bar diameter, type, spacing, correct location, and the number of bars that should be included in a Structural element. It should be very clearly shown in the drawings to avoid mistakes and confusion. An example for the correct order of bar notation in a drawing is a follows
Bar Notation
bars position in drawing
When it comes to a slab the order of notation of the top and bottom nets should be in mind.
also Check Stools in reinforcement , Cover Blocks , Crack length
