How to start your career as a technical writer (part-time) ?

Hi, I am currently working a full time job for an MNC based out of India and I want to do some part time work as a writer. I read a ton of books and I have good grasp on english but writing is something that I haven’t really done before.

I love engaging my creativity while writing anywhere, it could be a mail and I will do it functionally. I want a roadmap on how I could become a technical writer (as the pay is good) but only part time as I love my full time job as well.

I would really appreciate a fellow writer if they could guide me on how I could maybe upskill myself and start doing small projects. Which organisation would be the best to join if any? are there any global legit competition that I could partake in? How to build a portfolio?

Please don’t judge me in this draft. Thank you in advance for the responses.

TL;DR: Beginner writer. Need assistance on building portfolio.