jcli allows you to search, download, install, uninstall or upload a plugin.
First, please search a plugin by a keyword if you want to install it. You can get a plugin list by execute jcli plugin search zh-cn. You can install it with the plugin name.
For example, you can install the Simplified Chinese Localization plugin by jcli plugin install localization-zh-cn.

Download Plugins

Some times, Jenkins just cannot connect with the offical Update Center. We can use the download sub-cmd to download all the plugins which're you need, then upload them. This command will take care of the dependencies of the plugin.
You can try it:
jcli plugin download localization-zh-cn