Where to start with ChatBots?

I want to start my journey into ChatBots and how I can create them. I have read some articles regarding the type of chatbots. Basically there are 2 types of chatbots, one is a rule based and the other is a NLP/ML based. I am more interested in the latter and want some kind of started guide. I have read that these kind of chatbots usually use some kind of attention models (as they give state of the art results) like BERT. I have no experience in attention models. I have started with LSTM models and it's variations, as attention models have LSTM at their core I think.

What I want from the stalwarts in this field is some advice/starter guide (be it articles/blogs/videos) on how to get started or am I going in the right direction or not. It would really help a novice like me!

Thank you!