Entries are managed through the site.
You should log in to the site as a user of
Administrators group (or any other group, the users of which are allowed to edit entries).
The Control Panel password
differs from the user-administrator's password.
If you don't know the Administrator's password, create a new user with the respective permissions (Control Panel - Users - Add new user).
Login form for administrators works even if "Users" feature is disabled.