In Add Account, select QR login, scan the code with the Steam mobile app and approve the sign-in request after checking its details. HourIdler receives a Steam session token rather than your password. This is separate from signing in to the HourIdler website through Steam.
The token authorizes server-side account access and is encrypted at rest. Steam can revoke or expire it and require you to approve a new sign-in. QR login avoids sharing your password; it does not remove the need to trust the hosting provider.