How to access input elements in Grafana

Dear Grafana Team,

I am a beginer in JavaScript and Grafana. I added some drop down and text Input Elements in my Dashboard. I want to Access this fields and build my query. For this I am using the simple json datasource example. J found out that I can use the query method in the datasource.js. How can I Access here the Input and drop down field? Is there a documentation? I will be very happy About every help. Thanks!

Best regards,
Hakan

I am having the same issue but raised it under support