Plugin not showing in main menu

I think you can only add a group to main menu, so e.g:

<group id="MyGroup" text="My G_roup" description="My Group" popup="true">
  <action id="jplugin.Allaudin" class="com.mallaudin.jplugin.Allaudin" text="Plugin Name" description="Plugin Desc">
    <keyboard-shortcut keymap="$default" first-keystroke="shift ctrl alt B" second-keystroke="shift ctrl alt X"/>
  </action>

  <add-to-group group-id="MainMenu" anchor="first"/>
</group>

Not sure about the keyboard-shortcut.

this should work too:

<actions>
 <group id="Id1" text="Plugin name" description="Plugin actions">
 <add-to-group group-id="MainMenu" anchor="last"/>

<group id="Id2" text="Hello action" description="..." popup="true">
 <action id="Id3"
 class="com.plugin.action.Hello"
 text="hello!" description="..."/>

</group>

</actions>

shortcuts may be manually assigned by user in settings.