Pathway : Your network > Points of sale > import dealers
-> This empty file with header is particularly useful for creating dealers.
To import dealers with a file, you need to select an import format then follow the fields expected in the import.
The best way to do it is to download a model of the format you want in Your network > Points of sale > import dealers button then click on the tab export, then choose your format for "Export empty file with header" like this : 
You will get a file like this :
It is not necessary to fill in all the columns, but they must be present except the dealer id "_id" if it's about updating a dealer because the matching is done with this data that ensures a perfect match)
When creating a dealer, this field is not expected because the dealer does not yet exist in the database so the "_id" so the ID doesn't exist either.
Edit the file like you need then import it in the backoffice.