As the name suggests, the 'auto-detect delimiter' option in Sync automatically recognises certain delimiters as column separators when you are adding files. E.g., if your data is separated by commas, tabs or other common delimiters, Sync separates the data into columns accordingly.
You can ignore 'auto-detect delimiter' and choose your own delimiter. This is useful if your data contains other delimiters (e.g., a ^ symbol).
To do this :
Leave 'Autodetect delimiter' unticked and enter a delimiter in the field below it, as shown in the image below.
This is available when adding individual or multiple files, via the 'Data items' tab and Add > File or Add > Directory.