I am not surprised I’m talking nonsense – I did say I was very confused! I’ll try not to take your admonition too personally, however.
I came to the nameserver conclusion as a result of these three Q&A’s, which I have copied and pasted from the WordPress site:
Q: How to I map my wordpress.com blog to a subdirectory of my current domain such as https://domain.com/blog ?
A: I’m sorry, but subdirectory mapping is not available. You could map to a subdomain as described below.
Q: I own domain.com, and want to map a subdomain of that to my WordPress.com blog. Is that possible?
A: Yes. You will need to add a DNS CNAME at your DNS provider before the domain mapping will work. You should not change your nameserver information if you just want to map a subdomain. The CNAME should look something like the following:
subdomain.domain.com. IN CNAME [your-blog].wordpress.com.
Once that DNS entry has been added login to your WordPress.com Dashboard, click on Options > Domains and enter subdomain.domain.com into the box. If everything is setup correctly, it will allow you to map the subdomain to your blog. If things are not quite right the system will let you know and provide suggestions on what you need to do to remedy the problem.
Note: You cannot map only the “www” subdomain since we remove the www from all the URLs at wordpress.com.
Q: I own domain.com, can I map that to my wordpress.com blog?
A: Yes! Here is what you need to do:
Go to your domain registrar and change the nameservers to the following, being sure to remove any existing nameservers that may be there:
ns1.wordpress.com
ns2.wordpress.com
ns3.wordpress.com
If your registrar needs the IP addresses:
72.232.101.25
69.90.211.204
207.7.108.237
Then you need to wait. DNS propagation could take up to 72 hours – though it is frequently less.
Go to https://dnsstuff.com
In the top right is the DNS Lookup box – enter your domain name. If it says our nameservers, you can proceed here. If it does not you need to wait some more until it does.
In your blog click Options > Domains
Put your domain name in the box, click ‘Add domain to blog’. Your domain should then appear as a choice below that button.
Along from the domain name it will say “Put blog here”
Click that.
I am still confused.