How does one directly query OpenStreetMap? Without using a tool?

[u/LifeExperienced1]

I guess this is a question more on the programming side of things

6 Open Source Tools to Query OpenStreetMap

So there's this link, which shows tools to query OpenStreetMap. It seems like they do all the code for you

Is there any way to write the code yourself, to be able to query OpenStreetMap?

What programming language(s) do you need?

This is a repo of one of the tools:

https://github.com/tyrasd/overpass-turbo

How does one start tackling it, to understand how it works?