Are you looking for the designer to look at the plan and suggest modifications, choose finishes and colours, do room layouts and lighting plans, buy furniture, bedding, kitchen equipment, light fixtures, lamps, artwork, window treatments, audiovisual/security/home automation systems, built-ins, and so on and so on?

When you say you want everything, do you mean all of this or only a portion. It's only when you are super specific that the designer can gauge how big a project this would be.

Are you also looking for them to be on site and liaising with the builder? Will they be doing all the ordering and making sure that everything is on site at the time it's needed?

If it's a project where the designer is truly handling every aspect of the job except the actual building, and keeping you informed through regular meetings, then it's at the highest end of design service. It's basically a bespoke job that's turnkey for you to walk into at the end and move your clothes and personal articles into.

Think about what level of involvement you expect to have. Are you wanting to be involved in every decision and having three or more options for everything? Are you trusting the designer to interpret your taste and provide what you're looking for without meeting after meeting?

Every job is different, and the designer is wanting to know how you expect the job to go and where you see the designer as your partner as you go through the process.

I wish you great success in find the right designer to work with you on your new home.

Cynthia nailed it. Figure out the answers to each of her groupings of questions -- visualize the degree to which you want control versus service, options versus somebody else to sort it out -- and then take the resulting guidelines to the designers you interview. From there, they should be able to narrow down what they need to know.