After theme installation a WordPress message will pop up at the top of the screen noticing you which plugins are required and which plugins are recommended for the use of this theme.
The link at the bottom left will link you to the install page.
On the install page you see an overview of all plugins required and recommended. You also see which version number is delivered with this theme.
You will always see the current status of your installed plugins on this page. So you can always check, install(including activating) and update your needed plugins here with the buttons in the Action column.
Please make sure to refresh your screen after installing plugins to see the corresponding menu items on the left menu.