It's ok, i was able to download the video and the .val
Took me a few minutes but i think I got it mostly figured out.
As a quick instruction for others looking for answers and before a good walkthrough is made..
What I did for the curve on the left that I wanted on the right.
click the "flip object by line"
choose the points of the part you want to mirror, making sure to hold down the control button to select multiple points/lines/curves etc
Once you have all of your objects selected hit the enter key to let it know you are done
then click the 2 points you are using for your center line (for me it was top center point and bottom center point)
a popup comes up (that i didn't much pay attention to)
click ok/apply and bam...mirrored.
Haven't done much with the "flip by axis" one yet though.