Does anyone know of a good place that defines how and what interview questions to ask or has some example interview materials to guide what I should ask during each interview?

BACKGROUND CONTEXT: I'm working on a single-matter assessment following the GRI's standards for materiality. I have completed the beginning stages (e.g., defining scope) and have made an extensive list of potential stakeholders to interview or survey. That list includes a) employees, b) suppliers, c) investors and prospective investors, d) experts in the same sector as my company, e) government officials, and f) one or two people from academia.

Stakeholder Engagement Plan of Action—All internal staff must take an ESG 101 course (given that we're a new program at the company) and then, at the end, take our survey defining material topics of priority. Essential leads of each BU will receive an open-ended interview. And for all the rest of the stakeholders, leadership wants to hold interviews with given that it is more personalized.

I have seen so many different guides online, all emphasizing the need for stakeholder engagement through workshops, surveys, and interviews. However, none of these guides provides any guidance on what those workshops should look like or what specific questions need to be included in your survey and questionnaire to ensure it holistically covers all material topics and ideas that will later be analyzed. Does anyone have any advice here? If you have any good sources, that would be greatly appreciated.