A simple script would add the dates when the Quote is changed to Sales Order

I want to add a script that is similar to what must be for quotes. 

When I enter a standard order I would like the default ship date to be 14 days from the order date. I really would like to know where to place the script (and the steps to get to that screen ) I don't want to have to change the default everytime i go into the module or remember to fix the ship date on every order

Thanks

I want to add a script that is similar to what must be for quotes. 

When I enter a standard order I would like the default ship date to be 14 days from the order date. I really would like to know where to place the script (and the steps to get to that screen ) I don't want to have to change the default everytime i go into the module or remember to fix the ship date on every order

Thanks

Attached to the order type field on Column post-validate.  This checks to see if the order type is S for Standard and it adds 14 days to the ShipExpireDate field

sDate=""
Ship=""
newDate=""
retVal=oBusObj.GetValue("OrderDate$",sDate)
retVal=oBusObj.GetValue("OrderType$",Ship)
retVal = oSession.FormatDate(sDate, newDate, "%M/%D/%Y")
newDate = DateAdd("D", 14, newDate)
newDate = oSession.GetFormattedDate(CStr(newDate))
If Ship = "S" then
retVal = oBusObj.SetValue("ShipExpireDate$", newDate)

End If

novice here, can you walk me thru where to apply this formula?