Lightroom Classic 12.4 Catalog question

In addition to what "smathia" advised, just a couple of tips, when you create a backup of your Lightroom Catalog a zip file is created which contains a back up of two files one ending .lrcat, which is the actual Catalog and one ending .lrcat-data which contains additional data. They are exact copies of those file when you exited LrC and created the backup. The zipped file is placed in a folder which is named with the exact date and time it was created so you should be able to identify the backup you need to restore.

The screen capture you posted of your current Lightroom sub folder containing your Catalog files shows two LrC 12 catalog files and -data file. If you view the folder in list view you should see additional info as the when those Catalogs were accessed and modified.

I think there may be something else weird about my catalog so I want to try restoring it from a backup.

Be specific. Tell us what is "weird", there are a lot of things that can happen that have nothing to do with catalog corruption.

The other lrcat files are catagues too. Look at the creation/modification dates for the latest one. My guess would be 12-2.

The lrcat-data contains the masks you created. You will need that too. Other files are expendables, but you can cary them over, no problem with that. 

The .lrcat file contains the database, so that is the most important. You can move the files anywhere on your disk. As long as you do not move physically the images files, Lightroom will find them. So there is no problem trying out the files first, before you move them to their final destination.

And yes, there are courses on Lightroom on the internet. https://jkost.com/blog/ and https://www.lightroomqueen.com are those sites with resources about Lightroom that I would trust. There are others around. If you want a pay for course, you will be good with LinkedIn Learning. They have great quality courses about anything. 

If you just double click on the .lrcat file from your backup lightroom will relaunch with that copy of the backed up catalog 

https://www.lightroomqueen.com/disaster-strikes-corrupted-catalog/