Becoming a ChatGPT expert is achievable with these steps:

1. Get to know the GPT architecture and its variants, as well as the basics of transformers and language models.
2. Understand how pre-training works, including the data and tasks involved and how to fine-tune the model for specific tasks.
3. Access the ChatGPT code and pre-trained weights on the OpenAI GitHub repository.
4. Give it a go by fine-tuning the model on different datasets and tasks, and see the results for yourself.
5. Read up on the ChatGPT and original GPT papers and technical reports to gain a deeper understanding.
6. Join the community and chat with other experts in the field to share your insights and learn from others.
7. Stay updated with the latest advancements by following the work of organizations and researchers in the GPT models and related areas.

Additionally, it would be helpful to try out the pre-trained models available on OpenAI's GPT-3 Playground, and see the difference between the models and which ones are best suited for different use cases.