请人指导的话该怎么说英语

To ask for guidance, you can say:

Can you please guide me on how to do this?
I'm not sure how to proceed. Could you give me some guidance?
I need some help. Could you provide some guidance on this?
I'm lost. Could you give me some direction on what to do?
Could you give me some advice on how to handle this situation?

You can also use phrases pke "show me the way," "point me in the right direction," or "lead the way" to ask for guidance.