Swift Package Manager - how to add package to an existing Xcode project

I decided to add a package to my existing Xcode project. Unfortunately there is a lot of information how to create a package and just a few lines how to use/add one. So if anyone knows how to add it, what to do and not to destroy my current project, please share your experience.

Swift Package Manager - how to add package to an existing Xcode project
 
 
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