Please follow the following steps for installation.
At first Unzip the zip you have.
Login to Joomla Admin Panel of your website and go to The menu "Extension -> Manage" (See Image - 1)
Click on Manage, then you will see there is options to choose file. Choose first component file then the plugin file Click on choose file Button and Select your Zipped File(Your extension) from your computer. Then Chick on Upload and Install button (See Image -2)
If the extension is installed successfully, then you will get the success message. So After installation, you will get the component at component->JK Open Graph and you will get the plugin at Extension -> Plugin Manager -> System - Open Graph Protocol For Virtumart.
Now you have to open the plugin and enable it.