If you buy your cabinets from a cabinet design company they will do the cabinet design work for free. Perhaps the source your GC is using will provide that service.

Who designed the house?

The general contractor is my husband's cousin who builds about five or six spec houses a year. He usually designs his own kitchens. In this case of course I want my hands involved don't want to design it with the designer. The person he uses just supplies the cabinets. He can get his handson any brand, Thomasville etc.We design the house with the help of an architect.

That's a tough one, our builder worked with a cabinet supplier that provided free design services.
In your case you may have to pay for the services of a designer.

I designed my own; most people use a kitchen designer.

Most builders work with supply houses that have KDs on staff. Beware though, as their cabinet allowances are usually pitifully low.I've seen them be as low as 5K for whole house cabinetry, which only works if you're doing the cheapest of the cheap.

Most of their allowances are pitifully low, actually. That helps them to get the job with an apparent low price. A low price that isn't so low by the time you plug in real actual products that you want to buy.