custom capability

Hi
I am new in plugin development.I have developed a module for friend.This module has four submenus.Out of four two should not be accessible to other user than admin & editor.

In other way how can I create custom role with custom capability.So that it will create on plugin activation.
I used this on my plugin activation hook.role is created but user with that role would not able to login to site.
Please assist me to create custom capability so that user with that capability shouls not create or edit posts ,pages.only access to dashboard.

Thanks

https://www.ads-software.com/plugins/capability-manager-enhanced/