Here I am adding how you people can use lookup lists from text files, how to build custom entities, how you can use custom intent recognition. I also struggled a lot use APIs of RASA initially so I made this video to explain to you how to hit API endpoints in your local systems.
Finally, you will learn something by watching my video about these above-mentioned things.
Note: I am new to create tutorials if you find anything annoyed takes it easy. 
Here is the link https://youtu.be/LJcONocPuAM
Looking forward to here feedback from you guys. 