I am moving this query to Photoshop Elements community, as experts there will be able to help you out best.
Meanwhile, you may take a look at these self-help documents:
The second link is important to understand how to transfer both your photo folders and your catalog to a new computer or drive.
If you install a newer Elements version on the same computer, you don't have to do a backup (even if it's always a good idea), you have to 'convert' the catalog. Remember you can use both versions on the same computer (they are independent) but you need a catalog in the new format, with your own organization data (tags, captions...)
That's what the conversion process is for.
Especially look for :
"Use (convert) a catalog of an older version"
Yes you can. When you install the 2019 version you will get the option to convert your existing catalog. So everything will remain the same.