The Constitution establishes a Federal Government and limits it's powers. That's the main thing it does.
Some folks complained and wanted a Bill of Rights.
It was debated because why say the government can't do what the Constitution doesn't give it the power to do.
The Constitution doesn't grant any rights. It acknowledges that there are some pre-existing, God-given rights.
It also says that just because some are listed, doesn't limit the rights to those listed.
The Constitution creates the FedGov, and describes it's limits.
That's all it does.
Lawyers and politicians have subsequently spent the last 200+ years trying to convince us that the Constitution means something that it does not say, and/or says something it does not mean.