After activating the theme, go to theme dashboard, in the sidebar menu, you will be directed to WordPress admin. To install the plugins ( WordPress Admin > Deep > Plugins ) click on “install” button and then click on “activate”.
After installing, the preferred plugin will be activated.
Generally, you have access to theme plugins from this panel and this section provides you installing, activating, deactivating the plugins of the theme. Also, you can have access to them from WP-Admin > Plugins.
Please note: Installing plugins rather than theme plugins, it should be done from WP-Admin > Plugins > Add New.Managing Plugins