doc: add building note for missing classes (#266)

diff --git a/content/cn/docs/quickstart/hugegraph-computer.md b/content/cn/docs/quickstart/hugegraph-computer.md
index 02233fc..a3a2885 100644
--- a/content/cn/docs/quickstart/hugegraph-computer.md
+++ b/content/cn/docs/quickstart/hugegraph-computer.md
@@ -224,4 +224,8 @@
 
 ## 4 算法开发指南
 
-TODO
\ No newline at end of file
+TODO
+
+## 5 注意事项
+
+- 如果computer-k8s模块下面的某些类不存在,你需要运行`mvn compile`来提前生成对应的类。
diff --git a/content/en/docs/quickstart/hugegraph-computer.md b/content/en/docs/quickstart/hugegraph-computer.md
index 7839921..5a06d56 100644
--- a/content/en/docs/quickstart/hugegraph-computer.md
+++ b/content/en/docs/quickstart/hugegraph-computer.md
@@ -224,4 +224,8 @@
 
 ## 4 Algorithm development guide
 
-TODO
\ No newline at end of file
+TODO
+
+## 5 Note
+
+- If some classes under computer-k8s cannot be found, you need to execute `mvn compile` in advance to generate corresponding classes.