Stop and start for tool change

How do I tell Sheetcam to stop the program while I manually change the cutting tool and how do I start it again?
At present as a raw recruit I have broken my input CAD drawing into layers with only one operation for each layer and have specified the tool to use with each layer. An auto stop at the start of operations at each layer with a manual restart seems to be required.
What about drilling operations where different holes are required. Do I have to have a separate layer for every drilled size hole?
After Sheetcam, The G Code is sent to Mach 3 -When I solve this problem!
Thanks,
tulari

In Mach3 go to Config->general config. You should find an option to stop on tool changes.

You can put all of your drill holes on one layer. In each drill operation use min hole size and max hole size to select which holes to drill. Only circles between these two sizes will be drilled. If you are spot drilling your holes first you can do all of them with one operation by setting the min and max hole sizes to cover all of your holes.