How do you know you don't already have it? I mean if you are new, how do you know?;) Just poking fun, at your expense albiet, but don't take me seriously.
Assuming you are looking at the old Garmin Connect site, there will be a link at the top right of the page that says 'switch to modern'. If your device is not supported by the new site, then you won't have that link.
It might be slightly different if you are using Garmin Connect that is intended for a country other than U.S.
That is the classic Garmin Connect. Not everybody has access to modern, and it has been rolling out in waves. Unfortunately, you just have to sit tight and wait until your account is transitioned over.