How much light for chicks each day? How do you separate light and heat

I have 16 total that are exactly one week old today (11 Australorp/5 Barred Rock). They are in my homemade rubbermaid brooder box with a light on top with a 100 watt red landscaping type light in the brooder lamp. Since they arrived 1 week ago, I have just left the brooder light on all night to keep the brooder temp at 90-95 degrees. I also open the blinds near the brooder in the morning so that they get nice sunlight during the day.

This site http://www.farminfo.org/livestock/chickens.htm says I need to put the chicks on a "light" schedule as follows:
1 to 6 weeks-----Lighting can be: a) 8-10 hours/day or b) 12-13 hours/day, gradually reducing to 8-10 hours
6 to 19-20 weeks-----Lighting should be held at 8-10 hours/day
19 to 20 weeks-----Lighting should be increased to 12 hours/day (egg production stimulated)
20 weeks-----Gradually increase from 12 to 16 hours/day

Is this true? Is it necessary? And how do I keep my babies warm with no light? I am sure this is a silly question, but like any mother hen, I want what is best for my chicks. Thank you for your help in advance.

 

Thank you for putting my mind at ease. And heat lamp bulb may be a really good idea for when they still need heat at night, but not light in the coop. Thanks again.