Looking for advice as a young person

I am currently 17 years old, turning 18 in about a month. I live in Finland if that matters.

I'd like to start investing once I turn 18 and can open my own accounts, and I'm looking for advice how should I start. I have around 10k just sitting on my account and I'm not sure what should I do with it. I could also be able to save a few hundred bucks a month, and I have no idea whats the best option to invest those in. I have tried reading advice online but I feel like i get very different answers from different sources, and im not sure if I trust them all too much. So if anyone could give me some advice I would be very thankful!