Help! Light a led without using the arduino libraries

Using Arduino Programming Questions
1

Hello.I need some little help. I'm trying to learn Arduino and I want to light an LED for one second (the 1 second time interval will be done by using a uC timer). But I'm not allowed to use Delay (), DigitalWrite (), basically I'm not allowed to use Arduino libraries.
How can I do?

2

Control the LED using Port manipulation

Are you allowed to use the millis() function for timing ?

3

Yes, I can use millis() function

4

I don't know the answer because I don't normally work with ports, but I do know that the answer is likely to depend upon such things as how is the LED wired, what pin is it connected to, and possibly what Arduino are you using?

5

I don't get it. Isn't millis() an Arduino library function?