For HTML files you could put the author, title, series etc values in the file name and specify a suitable template in Add Books->Reading metadata.
That said, I would just drop them into a library as-is, and then edit the columns in the book list - as if it were a spreadsheet.
I suggest you let calibre take care of the author_sort and title_sort columns, there are settings in Tweaks to control how it does that.
BR
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