I've been presented with similar versions of your question -- "If I have a good spec sheet that details exactly what I need done, when I need it, at a fair price, will you deliver?"
I think the proper approach, especially if you are not technical, is to just go over the spec. Talk about what I feel is properly fleshed out and where there may be some ambiguities. This way, hopefully, we end up with a situation where I understand your interoperation of the spec and you understand my approach. Any questions, we write down and either go over before commencing work or structure things such that we can address those questions in a reasonable way.
When freelancing, it really is about delivering what the customer wants, not my interpretation of what they want.
I think the proper approach, especially if you are not technical, is to just go over the spec. Talk about what I feel is properly fleshed out and where there may be some ambiguities. This way, hopefully, we end up with a situation where I understand your interoperation of the spec and you understand my approach. Any questions, we write down and either go over before commencing work or structure things such that we can address those questions in a reasonable way.
When freelancing, it really is about delivering what the customer wants, not my interpretation of what they want.