In the Project Management Module, the Time Sheets and Expenses are entered by the Employees. These entries will be approved by either the Project Manager or Administrator of the concerned Project .
Employee Center

This fig. above shows the Employee Center where the employees has the option to enter the Time and Expenses related to their project
Time Sheet Entry

Approve Time Sheet
The Approval process is done by either the Project Manager or the Administrator.

Go to Related Transactions< Time Sheets
You can see the time sheets entry in the Unbilled Status

Generate Charges
Step1 : Come to the Project Form
Step 2 : Charge Run History < Generate Charges

Clients To Bill

Billed Timesheets: Go to Project< Related Records< TimeSheets

So here all the time sheets entered by the employees are billed to the Client.