I have a 3rd party and the file that downloaded is a QB import/export file

Good question. I hate to use the answer "because that's the way it's been done", but....Our entry is broken down into about 20 line items and the POS generates ...

I have a 3rd party vendor between our QBO and POS system. I was able to download the journal entry from the POS as a QB import/export file. How do I upload this...