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Save the spreadsheet using the default format, in case you want to edit it later.
Export the spreadsheet to a CSV file.
In Excel, use File > Save As…, and set the “File format” to “CSV UTF-8 (comma-delimited) (.csv)” (preferred) or “Comma Separated Values (.csv)” then enter a filename and save it.
In Google Sheets, use File > Download > Comma Separated Values (.csv).
In Numbers, use File > Export To > CSV… and use the default options.
Navigate to Studio Home > Taxonomies and click on the Import button at the top right of the screen.
When prompted, click to select the CSV file from step 4 and upload it.
When prompted, enter a name for the new taxonomy:
When prompted, enter a description for the taxonomy (recommended but optional).
Then keep the page open until you get this message:
Find your taxonomy in the list of taxonomies, and click on it to verify the results:
taxonomy following How-To: Import and export a taxonomy guide.