If it's the first time you are doing this, the much simpler is to use the WinReducer Post Installation" OOBE Tool :
1. You prepare all executable files for your software (like *.exe or *.msi) in a folder you choose
2. Activate "OOBE" tool using the ON button.
3. Hit the button "Add a file", choose a file in your folder and your file will be copied automatically in the "WinReducerPI" folder (you could find it in your "HOME - SOFTWARE" folder)
4. Sometimes, you need to add a Pause to avoid launching to setup at the same time. But it will come with your experience. But you could add one, simply by using the menu on the top right of the window. Where you could find many other possibilities (color,...)
That's all !
After doing this, when you will Apply all your changes, the folder "WinReducerPI" will be copied in your ISO extracted folder. Then if you create an ISO you will see it, but if you use an usb key, please read "Caution" below.
And you will find a file in your C: drive named "WinReducerPI.cmd" which will automatically launch all your files. So, no need to launch it manually. It uses the RunOnce method. So it will be launched just before your 1st login. So if you don't see all software to install at this moment, there is a possible problem. After all software installation, this file is not needed any more, so you could delete it manually.
I left it there if you want to debug your file, in case something goes wrong during the installation. To debug it : open cmd window, move the file to the window then launch it. All software installation will start then you will see in the cmd window which one causes trouble.
The method I described is a "normal" method, I mean which uses setup installation software. But sometimes, you could use a silent method to install your software. But if you begin, it will be better to start as I described then later you will want to use silent switch with a better skill ...
.. But you could have an idea using the top right menu, at the end of the list (it's a winreducer forum link which redirected you to the thread where you could find many interesting silent switches for many software ...Caution
: Take care if you use an usb key, you will need to verify that the folder "WinReducerPI" is present on the usb thumb drive ! Otherwise it won't work.
Hope this will help you ...
EDIT : This is a WinReducer method, but you could find many others in the WinReducer "Tutorials" forum ...