Use the modelling controls in the Warper menu to modify the meshes to define the original and the final shape of the image. You can modify the shape and size of the patches or the location and orientation of the mesh, divide the patches into smaller subpatches, and split the edges into smaller segments.

If you cannot see the mesh properly against the colours in the image, you can customize the colours of the various meshes, as well as those of the splines, tangents, and vertices. See Display Settings.