Web Chatbot LLM Integration

I am a developer by background, and I am currently working on building a custom AI agent.
The agent is intended to read subscribers' chat histories and answer questions based on past conversations.
While I have experience as a data analyst and data scraper, I am not an LLM engineer.

I need a general guide and a simple script that would allow me to conduct initial testing.

Given this project is still in its early stages and I am operating on a limited budget.

Once documentation and python script are working, this project will be closed.

Documentation is mandatory and ai bid will be ignored. Only individual freelancers!

Thank you.