People can access the Sites application by signing in to your organization's ArcGIS Enterprise with their ArcGIS Enterprise account.
-           Open the URL for your organization's portal website.Note:You can also access the Sites administration app using the URL https://webadaptorhost.domain.com/webadaptorname/apps/sites/admin. 
- Click Sign In at the top of the portal website home page and enter your account credentials.
- Click the apps switcher button    next to your user profile and choose Sites. next to your user profile and choose Sites.