How do you measure data and make decisions based on that?

As the title says I want to learn how and which tools do product people in startups use to query data, make dashboards, do A/B testing and all that.

I'm working at a startup where none of this is practiced, so I want to know how other folks do it as most startups in the growth stage and above do this and expect the candidate to be aware of the tools, setup etc.