Ask HN: How to get started with SaaS?

I'm Computer Science Engineer and have worked as freelancer developer for the past 4 years. My life goal is to make a living running a SaaS business.

Ever since I learnt how to write code my dream has been to have my own SaaS business, however I struggle on finding how to get started with it.

Specially on what regards on finding a viable idea to convert into a SaaS platform.

Any advice on how to get started?