Need information on Prompt engineering (System message) and not access to internet.

[AdvaitKale01]

So I wanted to discuss on 2 things-

1. How can I define a system prompt or basic prompt engineering to the chat conversation? What are the role types? Like is there a system role for this? Example- Content(parts: [Parts(text: 'You are a helpful assistant who gives accurate answers to world history questions.'], role: 'system')

2. I have used the turn based chat type. And the model does not have access to internet. I am assuming model might be PALM. If I explicitly specify modelName:'gemini-1.0-pro' then I get no response.