In general, as those files are already on your Mac, the related step(s) can safely be ignored/skipped. In fact the Certificate and Prov Profile installer step for example is configured to only run in “CI” mode / in a CI environment and should be auto-skipped on your Mac.
Are you sure that you have the right signing files installed on your Mac? Can you archive the project in that directory from Xcode?
I’d suggest you to simply double click those files, to install them in macOS, then it doesn’t matter where those files are, Xcode will be able to use them