Thanks for getting in touch! I think the best option here would be to use Octopus to import and manage your certificate. That way, when you deploy from Octopus, you can have us create the https binding and apply the SSL certificate.
We have a documentation page with further details on how you can manage your certificates within Octopus.
Does this look like what you are after?
If I’m missing something, or if you have any further questions here, please don’t hesitate to let me know.