How do I change the old admin panel to new panel?

When I tried to put somebody as another admin, I couldn't find the thing you're suppose to do. I think it is in the new admin panel but how do you change the old panel to the new panel?

The option is in both admin panels

From old to new:
Ontop, you have a link New Version in the list of theleft frame

From new to old:
Ontop right, under the wording Administraton Panel, there's Old Version

You want an Admin:
Admin Panel => User Admin & Group Admin => Permissions

=> Type Username
=> User level (on top) => Administrator

Thanks for this information.