Please give me your advice.

On business, one of my suppliers sent me kinds of proposals about their newly launched services.
But those proposals were too abstract to consider.
In that case how should I respond to them?
Which expression do you think is the best among the below?
(If you have the other one, please let me know.)

Could you spell out them?
Could you explain them more concretely?
Could you let me know them in more detail?

Please give me your advice.

Thank you for your help.