You need to find someone who is willing to trade with you. Once you have an agreement to accept a trade, click on Departments > Labor > Exchange Professionals With Others. A window will pop up and you enter in the country with whom you will trade. You enter the numbers for each profession that you want and the numbers that you want to send and click on submit. When the other country accepts, the exchange is made.
You need to list your country name. Nobody can make an offer without it.