Risk means the possibility that an investment performs worse than you hoped, including losing part or all of the money you put in. Return is what you earn in exchange for taking that risk, whether through rising prices, dividends or interest. The two are linked: assets that offer the prospect of high returns, such as individual shares, tend to move up and down sharply, while assets seen as safer, such as government bonds or cash, usually offer more modest returns.
For a beginner, the practical lesson is not to chase the highest possible return without asking what could go wrong. A useful question to ask about any opportunity is what you stand to lose, not only what you stand to gain. Understanding your own comfort with ups and downs, often called your risk tolerance, helps you choose investments you can hold through difficult periods rather than selling at the worst possible moment.
There is no single correct level of risk. It depends on your goals, how long you can leave the money invested and how you react to falling prices. The aim is to take enough risk to make progress towards your goals, but not so much that a downturn forces you to sell or keeps you awake at night.
This content is general information, not investment advice.