Hello, I am working on a program that would automatically update the Production Journal for our production orders. Right now I'm trying to get the production journal lines for the production order via ODataV4 (as below), but I am having trouble.

I've created a web service, but when I use it, the results are empty. The web service looks like this:

Response I get:
{
"@odata.context": myURL,
"value": []
}
I believe you have to specify a journal in order to get journal lines, which may be the cause of the problem. I've tried to rectify this by adding ?$filter=xx like so myURL?$filter=Order_No. eq 'ORDERNUMBER' using this page but I just get an error in the response.
I've also tried tried to use the API to get the journal lines using this page. But it says you need to have the journal ID in the URL, I can't figure out what that should be. I've tried putting in the ID of the production order, the name of the production order, doesn't work.

If anyone has ideas I would love to hear them, I'm having a tough time with this. Thanks!