I guess you have two things here...
1. Fix the 'album' values for those already imported
2. Have them filled on import in the future
1. Fix the 'album' values for those already importedYou can try a couple before going wholesale, or just jump right in. Remember that you can hit Ctrl+z to undo if something doesn't look right.
Select one, a few or all of your imported photos.
Open the "Tag" window
Locate the "Album" tag. It will show [Varies] if you have more than one image selected.
Click to open the "Album" tag for editing, and type in there
=filefolder()Note that the 'equals' sign is very important and must be included. Copy and paste the blue text if you are unsure.
Press Enter.
Now all of your album values match the containng folder name.
2. Have them filled on import in the futureYou can achieve this using 'tag on import' rules. You need to have your root pictures directory in your auto import list, and auto import must, of course, be enabled, which by default, it is.
I am not familiar with your image workflow, and as you are just beginning with your MC image library, it's likely that it will change as you figure out what works best for you. This will get you started, just ask if there's anything else you need.
My images are all in sub directories of D:\Pictures so we will use that as an example you can adapt to fit your own scenario.
Go to "Tools > Options > Library & Folders > Configure Auto Import"
If your root images folder is not in this list of watched directories, hit the "Add" button, or, if it is there, select it and hit the "Edit" button.
In the section at the bottom, titled "Apply these tags (optional)", hit the "Add" button...
Expand the field list and pick Album.
Enter
filefolder() in the "Value" box
And now, OK your way all the way out of options and you should be all set for the future.
-marko