Submesh Vertices

I have a lot of experience when it comes to meshes, ive worked with procedural meshes in unity for a while, but i wanted to ask, how do submeshes work ? I am looking through the wiki and ive read that submeshes are pretty much the same as meshes, yet i cant seem to find how to set vertices of a submesh? is there a way to kind of make a seperate mesh , apply the vertices, triangles, uvs and make it a submesh? I cant find a submesh alternative for setting vertices, i kind of get how it works but there isnt as much documentation on submeshes as there is with meshes.

Basically, how do i use submeshes like i do with meshes?

Submeshes use the same exact vertex list as the mesh, they are just additional triangle lists.

See Unity - Scripting API: Mesh.SetTriangles and Unity - Scripting API: Mesh.CombineMeshes