Update index.md

docs-en/13-operation/index.md

@@ -2,9 +2,11 @@
 title: Administration
 ---
 
+This chapter is mainly written for system administrators, covering download, install/uninstall, data import/export, system monitoring, user management, connection management, etc. Capacity planning and system optimization are also covered.
+
 ```mdx-code-block
 import DocCardList from '@theme/DocCardList';
 import {useCurrentSidebarCategory} from '@docusaurus/theme-common';
 
 <DocCardList items={useCurrentSidebarCategory().items}/>
-```
\ No newline at end of file
+```