ANSWER:
By default you will get to see only Administrator and User roles while creating an employee.
The remaining roles visible under Admin Options–>Roles are for the system to internally assign to an user based on the responsibilities given to an user. These roles are:

1. Expense Entry Approver
2. External User
3. Project Manager
4. Team Lead
5. Time Entry Approver

PLEASE DO NOT DELETE these roles in your account. The system will automatically assign these roles to the users, for example, if you made employee A as the project manager while creating a project, the system will grant him certain privileges which are specific to a project manager. These privileges may include the rights to edit the project details, creating tasks, timesheet approval etc.,

While creating the employees you can select only Administrator or User. Please choose user if you want him to get the limited privileges of the above mentioned roles. Whenever you select these employees for project manager or team lead role the system will internally grant them respective privileges.

If you want to over ride these privileges to these roles, we would suggest creating a new role with a different name and grant privileges to the new role. The newly created role will be available in the drop down while creating an employee.