Need to Edit a Form to Automaticly move to the next filed by pressing enter

Need to Edit a Form to Automaticly move to the next filed by pressing enter

Hi There
I need Help
I Have the following Form Created, and i need to modife as described bellow
 
1. Date Time            - Need That The Date and Time will be choosen Automaticly
2. Drop Down Menue - Choosing sales rep - and move to the next filed
3. Number Filed - Scanning Barcode - after it will scan i need it to move to the next Filed
4. Number Filed - same
5. Number Filed - same
6. Number Filed - same
7. Number Filed - same
8. Number Filed - same
8. Radio Botton - After Choosing up or down it will update the files