Seems we're getting somewhere. Here's what I'd suggest:
➡ https://flyawaysimulation.com/downloads/files/2684/fs2004-st-maarten-princess-juliana-intl-scenery/
The first file on that page is probably the one you have juliana2.zip.
The second one was it's predecessor juliana.zip.
Do a ZipDive of both files and copy the readme's of both files... in both cases they are named: Juliana/Readme.txt at the top of each ZipDive page.
If you compare the two readme files now, you'll notice that the author didn't include installation instructions in the original file. Hence - the instructions he included in the updated version would be referring to his work - the original version.
However, this doesn't tell us how to actually install juliana2.zip. Grumpy wrote a nice (scenery) tutorial for FS2002 and my guess is he hasn't bothered updating it for fs9 because there is no need to. Give it a try, you might just find that you'll be revisiting that little treasure trove called 'Grumpy's Lair' on a regular basis.
Let us know how you're getting on
😀