Ok maam the link has been added to the k rock update video description now I hope this helps you and wish you all the best on your home improvement projects.
I didn't use a track I used 2x4s for a frame but I started a peace on the first corner and cut the last peace to match the other corner then placed tin corners over where they met the next peace on the side I bought the tin corners covers when I bought the skirting I do have an instalation video as well on my channel titled Building K-Rock Underpinning Frame I really hope this helps with your delema