How do I go about using a server to store and retrieve data?

I have the task to implement a server into my Unity game which I must use to store and retrieve data. The thing is, I know nothing about servers and online databases. Where do I start? And what are the steps I need to stake to just store and retrieve a couple of stats from the game?

Here is the task:

"This is similar to Leaderboard, but the saved data must go on a server somehow. Integrating with Google Drive, a database, or even a simple Node.js server that keeps track of stuff in an array are all valid methods. The server/database does not have to be persistent, we just need to see that data is being passed off to a foreign location where it will be held until requested in the same session. Don’t worry if the server happens to be running on your local machine. It’s very common to have both client and server running on the same developer station when debugging."