You can take a look at this sample I made long ago. Straight lines are pretty easy, if you want lines that curve it gets a lot trickier.
you definitely don't want to be updating them every tick - only when you create them or need to move them.
if you get stuck, it is easier for us to help if you post a sample project...
https://www.rieperts.com/games/forum/Bezier_Curves.capx