In order to have the app asigned to the user, please go to the applcation setup page from within your Okta Administrator Dashboard. Select the "Assignments" tab, and click the green "Assign" button on the upper left side. Select the "Assign to People" optin, search for the desired user and assign the app to him. Click the "Save and Go Back" button, and the user should have the app assigned now, If this does not fully resolve the matter, please feel free to open a Support Ticket and me and my colleagues will be more than glad to assist you regarding this.
Stefan Pescaru Technical Support Engineer Okta Global Customer Care