New to investing

If you earn dividends, you add them into your normal Form 12 annual income tax return.

If you make a capital gain on the sale of assets, you do a CGT return.

Degiro claim they enable investing in the Australian stock exchange ASX. The Australian stock market is not like the US or most other markets, which are very focussed on investers realizing gains through hoping for appeciation in the share price, with them having to be sold to realize a gain. The Australian market tends to feature companies that pay far higher dividends than is the international norm, with probably less movement in the share price being a trade off.

I don't know how Degiro works and whether you actually end up owning foreign shares or if they do it through a company that owns them on your behalf - which might be the case here as they associate the name Morgan Stanley with their ASX mention. If it's a third party owning the shares, their fees are likely to make it a not so great proposition. So you would need to do some research into how any Irish accessible trading platforms work in this regard.

Apart from that, there would also be an element of needing to think about fluctuations in exchange rates as the aussie dollar is currently more expensive than it's been for several years, due to the war in Ukraine, so now mightn't be a good time to invest in ASX companies as a normalisation of exchange rates would see you having a paper loss on the capital value of ASX shares, even if their A$ valuation hadn't changed.

If there is a financially efficient route to investing in the ASX, it would be well worth consideration in terms of dividend returns, as they are world class; as in a 5% dividend PA being easily achievable as an average, at the moment.

There is no such thing as an investment that you will 'not lose the money'. No matter how safe it is deemed, you can still very much lose money, just to be prepared.