Newbie-problem? Cant get access to grav-admin panel after starting GRAV

I start Grav (after starting Apache) with http://localhost/grav-admin. Then I reach the page with the Quark-theme, but not the admin panel.
Whats wrong?

@pamtbaau:
Have you tried localhost/grav-admin/admin to access Admin?

Thats it!!!!
Thank you!

@Vic13, When a reply contains the answer to the main issue, then please tick the 'Solution' icon of that reply. The post is then being marked as 'Solved' which is an important indicator when people search for solutions.

By the way, documentation is available... https://learn.getgrav.org ;-)