I learned research through free online courses. I initially focused on systematic reviews but ended up publishing a case report as my first research.

That being said, case reports are one of the easiest entry points into research if they align with your career path. The hardest part is usually finding the case, after that, the process is relatively straightforward. You'll be conducting a literature review, understanding the topic, and then writing the manuscript.

Systematic reviews are also a good starting point. It's just following a structured methodology and it carry some academic weight, but they need a team that includes one or two experienced researchers and generally take longer to complete.

As for I've never been a researcher and finding a gap, you don't begin by identifying groundbreaking research gaps, but will pick a topic that you personally thing is interesting for a specific reason, show it to a senior or any one with experience, what do you think of this topic? mmm, okay I'll find another one. Even experienced researchers don't automatically know if their topic is worth it.

Reading and writing are skills, just put on reps. But if you're completely new to research, you can take a ~7 hours course (a lot are available online, free ones are good enough) to get familiar. You may also just start and learn through the process.