You have just installed VirtueMart but cannot see it on the Joomla! frontend.
There must be a Joomla! menu link to a component in order for that component to display. In Joomla! admin go to Menus/Main menu then select New. In the Select Menu Item Type list click on "VirtueMart". Enter a name for the link and save. VirtueMart will then be accessed from that link on the frontend.
If you want VirtueMart to appear on the front page when anyone goes to the site then in the Main Menu Item Manager make your new link to be the default (= default home page).