Error directing DNS CNAME to Netlify URL

Hi

I removed everything then only added offer.gizmo3dprinters.com.au
I clicked on verify and it gave this message " DNS verification was successful"
When I click on “Provision certificate” it shows a message box. When I click on that it shows this message "missing certificate

Let’s Encrypt is a fully automated install. We’ll provision a TLS certificate from Let’s Encrypt and install it on our CDN."

I closed the message box and it had this
" We could not provision a Let’s Encrypt certificate for your custom domain.

Please read our troubleshooting guide for some tips on what might be happening."

The troubleshoot says
" A Record for your bare domain should point to 75.2.60.5"
What should I enter as the bare domain?

The second part has this
The CNAME record for your subdomain www should have the value [sitename].netlify.app

I do have offer.gizmo3dprinters.com.au, offergizmo3dprinters.netlify.app
I am worried if I create www.gizmo3dprinters.com.au offergizmo3dprinters.netlify.app that it will break my site.