Secure HA with SSL

I am running HA 0.107.6. I have been using for a little over a year.
I use the NABU CASA cloud for remote access when not at home.
I want to secure it at home using SSL/TLS.

I thought I would be able to use Let’s Encrypt. I find the documentation limited and rather confusing.
Everything says I have to port forward 80 on my router. Why? But I did that anyway.
I have tried http challenge and based on the plugin documentation cannot use the DNS challenge since GoDaddy is my DNS provider.

I have the Let’s Encrypt plugin installed. I have a completely functional instance of HA.
Could someone please explain to me what I might be missing to complete this?
I have a legitimate email specified, taken out for privacy

email: <email>
domains:
- td2.info
certfile: fullchain.pem
keyfile: privkey.pem
challenge: http
dns: {}

Bottom line is I want to access my HA instance (two of them) over SSL/TLS. How can I get/generate a proper cert for that to work