Running at night is a useful skill to develop. Many ultras have some degree of night running. Checking the start time and cutoff time of your race, then checking the morning and evening civil twilight times, is always a good idea. Civil twilight is the point where the sun is 6° below the horizon. In most cases, this is the time when it is possible to see your surroundings without a flashlight.
Running at night is relatively straight forward, just plan a few runs after dark. If I'm running a race that requires running through the night, I'll plan two types of runs: A very late run and a very early run. The late run usually starts around 10pm and ends around 2am. The early morning run starts around 2am and ends around 6pm. The idea is to acclimate your body to running during the hours you'd normally be sleeping.
If you will be using an artificial light, most people use either a handheld flashlight or a headlamp. I would recommend carrying both. Use the flashlight as the primary light source and the headlamp as a backup. Since the flashlight can be carried near the waist, it will cast longer shadows on the trail. This makes it easier identify and avoid obstacles like rocks, roots, and cobras. The headlamp is useful if you need hands-free light, like eating at aid stations or pooping.