Hi,
You can try to use the text area to see which fields are needed:
Turn off the update option and put only one line in the text area with somethign random like qwerty
That will display an error message with the list of fields you can use.
Also note that you don't have to enter all the product information when you update your products.
You can just use the product_code field ( that's the field used by the system to look in the database for an existing product with the same name ) and the field you want to update.
For example, if you want to set a weight of 1 kg to your products you can use that:
product_code,product_weight,product_weight_unit
product_code1,1,kg
product_code2,1,kg
All the data already in the database will stay and the new information will overwrite the existing one (make sure you use the latest version as updates are not possible with previous versions).
There is no export yet. We just released the update feature of the import last week so it's going to take some time before we have an export of products.