The easiest way of installing a WordPress plugin is to use the plugin search. The only downside of this option is that a plugin must be in the WordPress plugin directory which is limited to only free plugins.
The first thing you need to visit your WordPress admin Dashboard area then navigates to Plugins » Add New page.
After visits, You will see the above page. Then from the right search bar, you can search any plugins using keywords, authors, or tags. After you found your design plugin you just have to click Install Now Button. After that you’ve to click the Activate button and it will become Active.
That’s It, Have fun.