The Taiwan consensus is basically an agreement between people in Taiwan about how they want their government to work. It's like when you and your friends agree on the rules for a game you want to play, so that everyone knows what's expected of them and there's less argument or confusion.
In Taiwan, there are two main groups of people – some who think Taiwan should be its own independent country, separate from China, and others who think Taiwan should be part of China. The Taiwan consensus is a compromise that both groups can agree on.
It basically says that Taiwan is its own country and has its own government, but it also recognizes that there is only one China, and that Taiwan belongs to China, but is not under the control of the Chinese government. This allows both groups to feel like they're getting what they want.
The Taiwan consensus is important because it helps the people in Taiwan work together to make decisions and solve problems, instead of fighting with each other. It also helps Taiwan's relationships with other countries, because it shows that Taiwan has a stable government and that the people there are able to work together to make things happen.