I am not interested in watching stock exchange rates all day long. I just want to place it somewhere and let it grow
Your intuition is spot on! To buy & hold is the sensible thing to do. There is no need to constantly monitor the stock market. To invest successfully you only need some basic pointers. People make it look like it's more complicated than it actually is for individual investors. You might find useful some wisdom pearls I wish I had learned even earlier.
- Stocks & Bonds
Stocks & Bonds are the best passive investment available. Stocks offer the best return, while bonds are reduce risk. The stock/bond allocation depends of your risk tolerance. Since you're as young as it gets, I would forget about bonds until later and go with a full stock portfolio. Banks are glorified money mausoleums; the interest you can get from them is rarely noticeable.
- Index investing
Index investing is the best alternative. How so? Because 'you can't beat the market'. Nobody can; but people like to try and fail.
So instead of trying, some fund managers simply track a market index (always successfully) while others try to beat it (consistently failing). Actively managed mutual funds have higher costs for the extra work involved. Avoid them like the plague.
Look for a diversified index fund with low TER (Total Expense Ratio). These are the most important factors. Diversification will increase safety, while low costs guarantee that you get the most out of your money. Vanguard has truly good index funds, as well as Blackrock (iShares).
Since you can't simply buy equity by yourself, you need a broker to buy and sell. Luckily, there are many good online brokers in Europe. What we're looking for in a broker is safety (run background checks, ask other
wise individual investors that have taken time out of their schedules to read the small print) and that charges us with low fees. You probably can do this through the bank, but... well, it defeats its own purpose.
- Tax advantages
US citizens have their 401(k) accounts. Very neat stuff. Check your country's law to see if you can make use of something similar to reduce the tax cost of investing. Your government will want a slice of those juicy dividends. An alternative is to buy an index fund on which dividends are not distributed, but are automatically reinvested instead.
Some links for further reference:
Investment 101, and why index investment rocks: However the author is based in the US, so you might find the next link useful.
Investment for Europeans: Very useful to check specific information regarding European investing.
Portfolio Ideas: You'll realise you don't actually need many equities, since the diversification is built-in the index funds.
I hope this helps! There's not much more, but it's all condensed in a handful of blogs.