Here is a nice video demonstration by AskMe2Buildit showing how we should place rebar (reinforcing steel) in the footing.

A rebar (short for reinforcing bar) also known as reinforcing steel, reinforcement steel, rerod, a deformed bar, reo, or reo bar, is a common steel bar, and is commonly used as a tensioning device in reinforced concrete and reinforced mansonry structures holding the concrete in compression.

Rebar can be very dangerous so be careful. Use all construction safety gear and make sure to be safe.

Reinforcing steel must be at least 3″ from the soil, thats why is important that you make sure your footings are level clean and all the corners and cleaned and straight. Like the footing you see in the video use dobies, masonry blocks or steel stakes to support your rebar above the ground.

The operlap is determined by the structural engineer and is typically formulated and shown like

lap = rebar thickness X#

Remember to tighten the rebar with tie wire as much as possible this way you wont have issues when you are pouring concrete in your footings.

A section of asphalt will have a min of 6″ of agregate baseand 3″ of asphalt.

Here in this video, they guide us with some very important tips for installing rebar (reinforcing steel).