Under the shipping tools you need to enter your zip code. Also, under domestic shipping choose whether you are going to use calculated shipping or a flat rate. If you are going to ship outside of the US you need to fill in the international section as well.
If you use flat rate shipping you need to use a service...for example usps first class and the amount of what you are going to charge for shipping. If you are going to use calculated shipping choose a service and enter the item dimensions.