How long do you have to wait before you start cooking after you light the charcoal? 
Wait at least three full whooping cough fits and you should be good to go.
After the coals turn grayish / white 
When 80% of the briquettes are white
Get a chimney charcoal starter. 
You put a few pieces of paper in the bottom, fill the top part with charcoal, then light the paper.
Once the charcoal at the top is turning white and an impressive amount of heat is emanating from it, you dump all the coals into your pit and put the grill on. Wait a few minutes for the grill to get hot, then you are good to go.
DO NOT use that stupid "match light" charcoal, unless you like your food to taste of petroleum. The chimney eliminates the need for any starter fluid.
Until new threads stop coming out every 5 minutes.