From a Bachelor degree in Physics to an internship in a HF

Hi, this is my first time writing on this forum, thanks to the advice of a dear friend. I've recently obtained my Bachelor degree in Physics and I was searching for a small internship opportunity in the financial world. I have pretty a strong basis in Python programming and data anlysis, so, based on this fact, that friend of mine adviced me to search for an internship in quantitative research in some HF, like Citadels. I have no real knowledge about some of the things many internships ask, like NoSQL databases or "distributed computing using MapReduce". I was wondering if someone here could give me some advices to build up this knowledge or eventually give me some tips about internship opportunities for a physics gradutae