Ethics is a branch of philosophy that is concerned with classifying human behaviour as right or wrong. There is a huge amount of literature available on the subject - far too much to discuss here in detail. The main question is whether your project may have any consequences that might be deemed wrong in some way. Usually this refers to the impact of your project on other people, but could also include impacts on the environment in terms of the energy used, greenhouse gases released, harm done to plants or animals, etc.
In the case of other people, you will usually be required to provide evidence that you have thought carefully about the potential impacts that your project might have. Universities often provide checklists to help with this process.
Any people that are involved in your project such as survey respondents or experimental subjects, for example, must explicitly agree to take part in the project and they must be free to refuse to take part if that is what they wish. In order for them to make the decision to take part or not, you as the researcher must explain to them exactly what they will be required to do and how the data that you collect will be used. This is known as the principle of informed consent.
For any project that involves other people, you will need to plan your process carefully so that includes a briefing for participants where the purpose of the research is explained, and you will need to collect explicit consent from them in the form of a signed form.
You will need to be particularly careful if the data you are collecting includes any data that could later be used to identify your participants. Personal data of that kind is protected by legislation in many countries including the UK, the EU and the USA.