Hi,
Sorry, we don’t have a tutorial on merging multiple projects. Our best advice would be to look through our documentation on project types to understand the type of the project you are using, and where it stores the lists of files and settings.
Then, you can try editing these locations manually to merge the settings from different sources.
If you could let us know the type of the project (per the documentation page), we can share a few pointers, but this will still require non-trivial editing of configuration files, and many need some troubleshooting.