Login to the Grid control and click on setup on top right of the web page:
then click on Administrators.
Here you can create Administrative users that you want to create and grant access to the available targets.
Fill in the details of the user:
Assign any roles that you have already created.
Now grant the targets if any .
Now grant the privileges by clicking on the ADD button.
Assign the view that you want.
Here I didn't pick any system view since I don't want this user to have any system privileges.
Click Next and then Finish.