I've posted this on StackOverflow, but on reflection this seems a more appropriate location.
This is quite a common topic to come up - wanting to use a custom host for a blogger blog. My personal reasons are due to issues concerning iframes, SEO and the specific address of the blog.
I have the custom domain already, and I am familiar with the necessary steps to use it with blogger (quickly outlined in such resources as http://www.wikihow.com/Use-Your-Own-Domain-on-Blogger.com)
My question relates to the manipulation of the DNS administration.
I do not actually know what the A and CNAME records do. Moreover, the step requiring the CNAME record attachment of ghs.google.com produces an error, as it conflicts with a previous CNAME record already listed (duplication of records). I could delete this extant, conflicting record, to attempt to solve the problem - but I would be doing so blind and may consequently move from what is a slight inconvenience, to a very serious headache. I am also wondering if there is any security risk in this pointing operation, as I have seen no mention of it either way so far.
One final issue, albeit one which I am not overly concerned about, is whether this pointing could interfere with other pages in this domain (if I opt not to use a subdomain).
Perhaps I am not entirely understanding the process: how will the address of the blog change if the location of its files (and therefore the blog itself) does not?
Sorry about how noobish some of the question is above. Any direction or information relating to this would be much appreciated.