Changing Grasshopper output with contour visible

This is what I’ve done, and but i want to see the contours just so i can have a better visual on the surface output
right now, it is a bit unclear. How can i achieve that?

As always, posting a bit of code would help. Are you referring to ‘Display | Preview | Custom Preview’?

Hey thanks for replying!
i think that is what i am referring! but i found it , it is just toggling the “Preview Mesh Edges”