@Fares You need to see this to get the idea Conversational AI chatbot using Rasa NLU & Rasa Core: How Dialogue Handling with Rasa Core can use LSTM by using Supervised and Reinforcement Learning Algorithm | by Kunal Bhashkar | Medium
If you a beginner in Rasa and creating a chatbot, just create some basic chatbot and soon you will get all the knowledge and working practise whilst using RASA, NLU/NLP and ML.
I will encourage, take step by step process if you don’t have any prior experience in the domain of NLP and ML. If you are expert then you can create any ML pipeline as per your requirement and business logic.
I hope my points are clear to you?