There are cases when you need to run some G-code to prepare the machining center before the Prism program can run. For example, if the machining center has a fourth axis that needs to be initialized.
There is a feature in Prism which lets you do this. Here is how: create a subprogram to run before the Prism program and store it at position 98. Create a subprogram to run after the Prism program and store it at position 99. Then enable the setting called Machine Preparation Subprograms in the machine settings. The Prism programs will now call those subprograms at start and end.