If you want to buy a second-hand house, first of all, you should think about the house price you can accept and the requirements for the location of the house, and then tell these requirements to the real estate agents, because these agents will have a lot of resources. As long as there is a suitable house for you, they will call you to see the house, but if you buy a house through an intermediary, then you need to pay a certain percentage of the agency fee. Personally, I think it is better to buy a house through an intermediary. After all, we don't know how to trade houses, how to apply for real estate licenses, and some people's houses are mortgaged. If they buy such a house by accident, it will be very troublesome.
You can also search the house on the internet yourself. There are many second-hand housing networks on the Internet now. You can find some houses nearby through these websites, but these houses are generally published by intermediaries, and few individuals put them online, so even if you value the houses online, you will eventually trade through intermediaries.
Another way is to ask people around you to help introduce some good houses, but the chances of buying a house through this situation will be relatively small. After all, the number of people we can meet is limited. Even if someone introduces us, it may not be that the house is suitable for us.