Conditional subscribtion

Hello. I am using your CF7 and your plugin to integrate my forms with with getresponse, I am just wondering how I can make it a conditional subscription.

For example

In my contact form I have a tick box “Do you want to subscribe to our newsletter”

If they tick this box I then want CF7 to send the email and the integration with get response to run,

If they don’t tick the box I just want the CF7 to send the email but no integration to take place.

How do I go about this?

https://wordpress.org/plugins/forms-3rdparty-integration/