Here's something you can try yourself:
1.) Locate a good location or somewhere dark if you just want to practice (remember to be safe)
2.) Tripod is a must unless you have super steady hands that can hold your camera at the same position for over 20-25 seconds.
3.) Camera settings - 'M' mode, shutter speed of at least 10-15 seconds, aperture of F16 and above, any white balance.
4.) Compose your shoot, start off with 15 seconds, F16, ISO 200. Take a pic
5.) Check the picture, make sure background is bright enough with this setting. Don't worry if your car is not bright at this stage. If too dark, change to 20 seconds and decrease speed if needed. Once you are happy with the background, move to next step.
6.) Using same setting, once you press the shutter, start pointing your torch on your zed. Move as fast/slow as you want, as long as you cover the light all over your zed. Best if find is to avoid lighting the ground, mainly just on your zed.
7.) Once done, you should get a good pic.
For star effect, up your aperture to max F24 but you will need to max your shutter speed to 30 seconds. If you zed is still not bright enough, you might need to use a brighter torch or you'll need to up your ISO to maybe 400 or 500. But doing that, you might find your background too bright hence might want to increase shutter speed to 25 or 20 seconds.
Play around with these parameters and experiment as you go. For them 'tron' lines, all you need to do is just walk around your zed, point the torch towards your camera and paint away. If your shutter speed is 20 seconds, you basically have 20 seconds to paint =)
Thank you! Definitely going to give this a go and I'll let you know how it goes =)