Install the IgniteBundle via
composer require jremmurd/pimcore-ignite-bundle
Now if you open the admin interface of your Pimcore application and open the Extensions tab in the Tools section, the new extension Pimcore Ignite should be listed. Click the install button and reload Pimcore.
After the Installation you should see two new user permissions for user presence and notifications. Also there is a new file called ignite.example.ymlin your app/config/ directory. You may now adjust the file to your needs, rename it to ignite.yml and then include it in your config.yml. For details on how to configure the extension please see configuration section.