I have created an introductory Dialogflow course for non-programmers and posted the videos to YouTube.
It explains Dialogflow concepts in the following order:
Usually, people are able to go through till step 3 without much difficulty. In step 4, there are a few things which should be done to get everything to work correctly.
Now, the simplest and quickest option is to purchase my Dialogflow for Non-programmers course because it has all the resource files included, plus I am available to answer any questions inside the course forum.
If you wish to do it by yourself, here is a checklist you need to follow to get your code working properly.
1 Did you create a Planets table in restdb.io?
2 Is it named Planets - the upper case P is important?
3 Did you actually populate the appropriate values inside the Planets table?
4 Do you know where to find the API_KEY for your restdb.io account?
5 Do you know where to find the environment variables for your RunKit account?
6 Did you actually add your API_KEY and DBURL from restdb.io into your RunKit environment variables?
If you have done all the above, and still facing a problem, get in touch with me via my contact form. (I will try and respond within a week).