It all depends where you work. Different companies have different requirements. Some companies have their own buyer who buys the different products so you don't have to order anything -- just keep an eye out for products that are late.
And usually, the project manager and buyer are in charge of the material. The coordinator just organizes the products to the right job.
There is a wide variety of material coordination jobs, so go to the interviews and listen to the requirements. I would not do anything else at the moment. I make OK money and my hours are flexible and life's almost good.