Your Resource Manager can use our Resource Load and Resource Calendar features to see your user team's workload across various timeframes (documentation here and video example here). As work is assigned to your resources (users) in the form of tasks, each of your resource must be a user in the system. However, not all users necessarily require a full license. You may be interested in our Time & Expense or Email Only licenses (free). In addition, you have the option of setting a license of 'None' for the user accounts.