How can we work without the details?

So, Boss told me to make CAD drawings for a project, but he was not sure what equipment we are going to use.
How can I make CAD drawings out of non-existent equipment? Pray, tell me? Especially because it’s a method of installation CAD drawings.
Good God.
Yes, I asked. He said he was not sure what the equipment is going to be and the submission is in 7 days (5 working days).
How is this even logical?!