Help with Customizing Time in Cell

[Kimberlyccr1]

I have a worksheet that has been driving me crazy and hope I can get some help. I have attached the worksheet. This worksheet is accessed by several employees at a time to input hours worked. The way it is currently formatted is a little more time consuming than I would like it to be. For example, if an employee starts work at 6:00 am, I would like to be able to enter 600 and have the cell automatically format it as 6:00 AM. I would like to do the same with the end time. Any help I can get on this would be greatly appreciated. I would love to be able to move on from this "project"!