What should domain "point to?" And also: "site name?"

We are trying to re-engage with our nonprofit's Homestead account, which was set up by others several years ago. We see that some of our domain settings reflect the name of a previous volunteer. In the Domain Center, our site is identified as "hstrial-name" (where "name" is a person's name). And in Subdomain setting, www has an arrow pointing to "hstrial-name." If we click on Change Site Association, it says our domain "is currently pointing to the website hstrial-name," and it provides a box where we change this setting, which says "Make domain point to hstrial-name.homestead.com." We do not understand these settings. Must we have our domain "point to" something? If we change our site's name and/or remove the "subdomain," will it remove our website?  Thanks for any help you can provide.