Well its not that difficult in Pro E 5. I will show how to make a simple punch in sheet metal.
First lets create a flat unattached wall onto which needs to be punched.
Once the wall is created we punch the sheet metal. To do this select the punch option as shown.
You can see the different punches available. Select the one required. There are three ways ways of constraining the punch. One is using an interface, i.e CS.
The second method is using the default position method. Third is manual constraining using constrains similar to that of Pro Assy.
Once constrained we can create a punch.