After a safety car period you will have a single-file rolling restart. These differ from normal rolling starts in a number of fundamental ways.
Firstly, with a restart, you will line up single file rather in a two-by-two grid formation. Secondly, with a rolling start as soon as the red light goes out the race is on however with a restart the race only begins when you cross the start/finish line so you cannot overtake until you cross this line.
As with a rolling start, if you are not the race leader, follow the car in front as close as you can but there is no need to look at the lights, just focus on the cars in front and as soon as they go: you go. If you are the leader back the pack up as you approach the last third of the lap, make sure the safety car has pitted before you increase speed. Try to catch the following cars unawares with when you get back on the power, if you can make a gap to the car behind here you will have a clear advantage.