Hi,
If you identify a "face" (officially a "face region") as "George", it will assocate that face region with a keyword named George. If a keyword named "George" which has the "Person" checkbox checked already exists it will use that pre-existing keyword. If it does not already exist it eill create it.
They keywords behave just like any other keyword. They can be found in the Keyword List panel may show up in various subsections of the Keywording Panel (I prefer using the Keyword List panel). As with any other keyword, using the Keyword List panel you can drag these keywords around to make a hierarchy. For example, you may want to create a keyword called "Family" and drag the "George" keyword under the "Family" keyword.
BTW, I'd suggest using full names as you may wind up with two different people both named George.
I also have a controversial suggestion which some people love and others hate, to use hyphens instead of spaces in the name. For example, "George-Jones" rather than "George Jones" like this
The value of this is that when searching or filtering you can more easily specify which "George" you're after if you wind up with many and the search/filter becomes more accurate. If you filter for keyword "George-Jones" you'll only get that one keyword. However if you had used a space between the names and you filtered for keyword Contains "George Jones" you'd get all photos that have either "George" or "Jones". If you changed "Contains" to "Contains all" then it would work better but you'd also get photos taken in "Georgetown" of "Fred Jones".