Still confused about launchers and installers

See step 4:

http://cubegames.net/development/beginners

I've read all the development docs and the Guerrilla Guide and I still perceive a significant gap when it comes to figuring out exactly what code I need to write and where.
I'm glad you've done legwork!

I'm told to download the default PortableApps.comInstaller.nsi, but I'm not told what to do with it. I downloaded the other nsi script that I'm supposed to customize. I did so, customized it, but that's all the docs tell me to do. I assume this file "includes" the other and creates the installer? But then what of the launcher, which is a separate exe and, I assume, a separate nsi script. All I have to do is add a command-line parameter to make this app portable. When I look at the source for, say, PNotes, all I see is the PNotesPortable.nsi which I thought back at the beginning was part of the installer, not the launcher.
The PortableApps.com Installer is in 4 parts:

1. The PortableApps.comInstaller.nsi, which is note modified by the user. You will compile this file, and it will gather all the other needed files, i.e. App, Data, and Other. When you develop, you would put the app in the PortbleApps.com Format. The "installer" is more or less a fancy zip file.
2. The PortableApps.comInstallerConfig.nsh, which is what you modify to specify the file name, etc.
3. PortableApps.comInstallerCustom.nsh, which is used if you need custom code. If you're curious, I can post more about it and the format, etc. This is only needed if the installer doesn't provide an option that you need.
4. PortableApps.comInstaller.bmp, which is not modified by the end-user, but needed for compilation.

The launcher will be PNotes Portable. (I'm glad you picked this one, I know what it does exactly :D). This is PNotesPortable.nsi. It (when compiled) creates the file called PNotesPortable.exe. You will edit this until it properly launches a portable version of your app. Then you can start packaging the app.

To package it, you will put a clean copy of the default settings of the app in App\DefaultData. Test it, cleanup the Data folder. The compile PortableApps.comInstaller.nsi. This is what you will upload.

I would be very appreciative if someone could lay out in precise detail what I need to download, what I need to write, and what I'm supposed to do with it all in the end to make the final package. It would then, of course, be awesome if the documentation was updated with this information to make it easier on future newbies.

Since I've been developing awhile, I kind of forget what I'm taking for granted. I will update the Guerrilla Guide with any information that will help people.

If you have anymore question, feel free to post about them. I won't have the internet after tomorrow(at least for the rest of the week), but even then, you can ask them and some other members of the forum can help you.

Also, if you can get onto the IRC Channel, people can help you there, giving real-time advice on the project. You can setup clients, or you can use the IRC Support Page