[TD-6689]<docs>: taosdemo user manual. (#8175)

documentation20/cn/02.getting-started/docs.md

@@ -177,6 +177,7 @@ taos> select avg(current), max(voltage), min(phase) from test.d10 interval(10s);
 ```
 
 **Note:** taosdemo 命令本身带有很多选项，配置表的数目、记录条数等等，请执行 `taosdemo --help` 详细列出。您可以设置不同参数进行体验。
+taosdemo 详细使用方法请参照 [如何使用taosdemo对TDengine进行性能测试？](https://www.taosdata.com/cn/documentation/getting-started/taosdemo )。
 
 ## 客户端和报警模块
 

documentation20/en/02.getting-started/docs.md

@@ -181,6 +181,7 @@ taos> select avg(f1), max(f2), min(f3) from test.t10 interval(10s);
 ```
 
 **Note**: you can run command `taosdemo` with many options, like number of tables, rows of records and so on. To know more about these options, you can execute `taosdemo --help` and then take a try using different options.
+Please refer to [How to use taosdemo to test the performance of TDengine](https://www.taosdata.com/en/documentation/getting-started/taosdemo) for detail.
 
 ## Client and Alarm Module