clarification of Step 4: The Code in the beginner_packaging post

Hello: Based on this post I have a couple questions to confirm proper understanding of the process. https://portableapps.com/development/beginner_packaging

1. The function of the portableapps.cominstaller is to just package up into a .paf.exe file which in turn load my app onto my device?

2. Do I still need to create a 'custom'.exe with NSIS to be added into my files which is packaged by portableapps.cominstaller? In reading different posts I thought at first I needed to use NSIS as noted in the beginner packaging step 4, (couldn't really figure that out.) Other post lead me to believe the portableapps.cominstaller took care of step 4.

Well I got myprogram 'packaged' and it install via the .paf.exe file. When I run the normal start.exe which is in macroportable, it is looking for _prog.exe which in the normal install start.exe sits in the same directory as _prog.exe.
Now that it's 'portable' start.exe cannot find _prog.exe as it sits else where.

I hope I'm explaining clearly. I think I need pointers to creating what some may have termed 'create a launcher EXE? So far I do not understand how to do this and any additional pointers or example is appreciated.