Create a PDF chat using open-source LLM

Hello,I'm interested in developing a product similar to ChatPDF. After trying various online doc/PDF chat tools, I found that ChatPDF offers excellent support for PDFs and interactive answers based on the PDF questions.For my project, I plan to include all the necessary preprocessing steps, such as converting to PDFA, performing OCR, and creating a vector database. Instead of using OpenAI's chatGPT, I'll integrate another high-quality open-source LLM model, like "lalama 2," or any other alternative with equivalent interpretive capabilities. The product will primarily cater to documents related to account sheets or legal PDFs.