SharePoint2013: How to add an app from App Catalog to a site

Scenario: How to add an app to a site from App Catalog.

Solution: On Site Collection click on "Site Contents" then click on "add an app". Then from the "Quick launch navigation" on the left click on "From Your Organization" as show in below screen shot:-

 
If you have uploaded the app to your Organization's app catalog, you should see it now. You then just click on your app to add it on to your site.