Where should I start if I know absolutely nothing about investing?

I want to learn about investing, but I have absolutely no background in it.

Basically, most of my friends work for companies that offer share schemes or other investment-related perks. One of them even works somewhere that gives employees financial advice and investment recommendations. As a result, they're all pretty knowledgeable about investing and the stock market. I'm definitely not.

They talk about investing quite a lot and seem to make a decent bit of extra money from it. I'm not talking about becoming millionaires overnight, but enough to make it seem worthwhile.

I've tried asking them about it. One mate can be a bit full of himself and is pretty dismissive whenever I ask questions. Another is much more helpful, but he's terrible at explaining things and somehow manages to make everything sound far more complicated than it probably is.

I've also tried looking online, but most guides seem to assume you already know the basics. A lot of the terminology just goes straight over my head. I'm not naturally good with maths or numbers (I still count on my fingers sometimes and use a calculator for basic sums lol), so a lot of investing content feels pretty intimidating.

Recently, I got chatting to our Head of Finance at work. He used to invest quite seriously and still dabbles now and then. I mentioned that I wasn't great with numbers, and he said that while understanding the numbers is obviously important, a lot of investing is also about understanding politics, economics, industries and the lay of the land—knowing what's going on in the world and thinking about how it could affect different companies and sectors. That way of looking at it really clicked with me because those are things I'm much more interested in and generally know more about. (No idea if that's actually a good way to think about investing, but it made it feel a lot more approachable.)

Unfortunately, it was also his last day at the company, and I don't know him well enough to message him asking him to show me his ways.

So, my question is: where should someone like me start? Are there any books, YouTube channels, websites or courses that explain investing from the ground up without assuming you're already financially literate? Or, for those of you who invest, what helped you the most when you were starting out?

I'd like to understand not just what to invest in, but why people make the decisions they do and how experienced investors think about the market. Once I've got that foundation, I'd like to learn about the practical side too—things like which platforms to use, common beginner mistakes to avoid, and any advice you wish someone had given you when you first started etc.

Any advice, tips, info you think a total novice like me should know would be great! 🙏