It doesn't matter whether you are an HR Manager or a third party recruiter, you still have to meet with the hiring manager to get a brief before you start hunting for candidates. 

If the hiring manager has no time to meet, your answer should be that you have no time to help recruit. 

Here are some great questions to get you started; you may even email this beforehand to allow the hiring manager some time to prepare.

1. What are the problems or issues you would like to eliminate over the next year? 

2, What are the 2-3 major challenges to be faced by the candidate in this position? 

3. What are the key performance indicators for his job? Be specific. 

4. Define 6-8 deliverables i.e. steps required for on-the-job success. In other words, what must the person in this job need to do to be considered extremely successful in this job? 

5. Define the Employee Value Proposition (EVP). Must clearly describe real needs and clarify job expectations. Here are questions that must be answered before starting any sourcing approach: Why would someone come and work for you? Why is doing this job at your company better than doing the same job at a competitor? Why do people come to work at your company and why do they stay? What specific companies have previously successful candidates and current staff worked for, before joining you? 

6. What is the background of the ideal candidate? What sort of role or job are they doing now? What title would they currently have? What industries and companies would you most like this person to come from? Why? 

7. Who will the new employee be reporting to? What is the nationality of the boss? What is the management style of the boss to whom the candidate is reporting?