I'd start by getting a good generalized background in the field of finance and technology so that you could identify what might be of most interest and demand for you.
Check out some of the free courses on Coursera:
Understanding Modern Finance
Essentials of Corporate Finance Specialization
Data Science Courses
A lot of FinTech jobs revolve around better use of data for innovative solutions in terms of investing, trading, managing, money and financial assets. That's on the tech side. There is a whole world of opportunities on the business side as well in terms of analysis, process optimization, change management, project management, etc.
It is a SUPER interesting field with established companies trying to figure out how they can leverage new tech, start-ups developing new ways of delivering services, and how they partner together is transforming the fields of financial services.
All the best mon ami.