To import from a spreadsheet, you need exactly ONE named range.  You select
the entire range of your data (all rows and all columns, including the
headers), then in the Name box to the left of the formula field, enter some
name you choose, like Contacts.  Save the spreadsheet.  Then when you
attempt to import the sheet in Outlook, you'll be able to specify that range
name when the wizard prompts you for it.  You should be able to map the
appropriate columns when the wizard asks you for the mapping, but you could
simply export the existing contacts as a CSV and use the headers it shows in
your spreadsheet so you can use the standard mapping.

Alternatively, you can save your spreadhseet as a CSV and import from that.
You won't need a named range in that case.