Microsoft provides an easy way for adding your staff to SharePoint. An Admin can access the Bulk Add Users page seen below.
This page provides you the opportunity to import an Excel csv file with the information needed to set your users up. There is even an example Excel worksheet that shows you the fields required.
Most small business have the information needed to produce this spreadsheet in their accounting or payroll application. For example, if your employees are in QuickBooks it is a snap to produce this spreadsheet. The only fields required are Display Name and User Name but I recommend you import as many of the fields as you can.
Once users are imported you can assign them roles and to the appropriate SharePoint Groups.
Even if you have a small staff, I recommend importing the information since it will save you time during setup.