I have a question if i have a group of vertices how do i fill them in with mesh
You can select 3-4 at a time and press ‘f’ to build faces.
Or you can select all vertices and press ‘shift-f’ to fill all the verts with triangles (they won’t really be neat).
Those vertices need to be connected with edges, of course (I say, just in case…). One can use Alt+F afterward to ‘beautify’ the triangle arrangement; repeat until no further changes are happening.
One can can use the Fkey > Make Fgons on a set of connecting faces: it hides some misery and ease up selection but be forewarned that those are not real Ngons.
Jean