Domain (URL)
When you sign up for a website, it doesn't matter if it's with Trackside or your own site, you have to own a domain. Anything within that domain is yours. Your domain will be (track/organization name) . tracksideapp . com or www . (track/organization name) . com.
If you're interested in a quick breakdown of the full URL just for reference sake:
http:// or https:// is a protocol. https is more common currently due to additional security measures.
The www. part is a subdomain, part of the full domain. Some sites use stuff like store. , this site uses howto. , and you'll notice from your Trackside site that it can even be your track or organization name.
again, for an example, this site's domain would be howto.tracksideapp.com. From the subdomain up to and including the, for example, .com, .org, .fr, or .llc is the domain.
You'd technically refer to anything after the domain as a path, similar to how if you have Windows and you're navigating files on your computer, When you're looking at files on your C: drive, that's still a path. Technically your pages are all files on a server, so you're just accessing files on another computer when you're going around the web, and your web browser makes them more than just 1s and 0s so you can interpret it. You can even use your web browser to access files on your own computer.