Trend trading is a kind of trading method, which investors or traders want to make money based on an asset`s momentum in a particular direction. When the price moves in an overall approach, such as up or down, that we call it a trend.
Trend traders buy when it is going higher, and asset moves in a clear uptrend and does sell it in reverse term. Uptrend usually creates a higher high and higher low, so when you connect the low points, the price moves overall above the trend line.
And you can sell when you see that assets create lower low and lower high. In this case, when you connect the higher points, you can see that generally, it moves under the trend line.