Forum Discussion
How to package a Windows Desktop C++ application together with its DLL dependency using MSIX
The way I got files into the package was to Add a New Folder to the project, rename the new folder the name of the project (i.e., myapp), then use File Explorer to copy the files into the new folder add them as Existing Items. Set the property of the added files to Content. Confirm success by opening the project's .wapproj file and searching for <Content Include="myapp\myfile">.
After publishing the app, locate it in C:\Program Files\WindowsApps\[package name]...\myapp\... You should see the files in there.
Re-reading the original post...
Manas solution should work. But you might consider adding the free VS Extension from Advanced Installer and creating the MSIX build project with that instead of the WAP. It sounds like your package should be simple enough to do (when you reference both the exe and dll projects you'll end up with both components in the package without manually adding it). More complex packages require purchasing the full product from them, but you shouldn't need that.