How does PostgreSQL work? Experiences?

Hey!

I have a question regarding databases. I came across PostgreSQL during my research on SQL databases. This is an object-relational database. How does the PostgreSQL work? Because I would use it on a Linux computer. And is it possible to run PostgreSQL over a cloud e.g. with a provider like Aiven? Or do I simply need suitable hardware and DB software? It is a big challenge for me, because I have never worked with an object-relational database. I would like to try it, because it supports SQL and JSON. I also read it has a graphical client included with most Linux distributions so I hope it will be easy to use.

Thanks in advance and best regards