Correct field and query to get my UDP data from Filebeat->Elasticsearch

I’m new with the whole elasticstack and had to plunge in rather quickly. I got 8byte double files via UDP and catch them with filebeat which is succesfully connected to Elasticsearch. The connection from Grafana to my elasticsearch server also works well.
Now I have a hard time to understand what metric and configurations I have to choose to make this stream of double values appear in a chart.
The current configuration of filebeat is this:

Among “field” I find now a lot of entries but nothing close to my “udp_test_1” field

I’d appreciate any help here. I feel like I’m just missing the last puzzle piece to finally understand how it works.