Please write to the international department giving details of the course you wish to apply for and why.

Hello! 

I would like to apply for the course which you offer in your International Deparment. Many have recommned me to sign up for it, saying that it will be of invaluable experience for me. The course which I specifically would like to apply for is for the one where I can manage and help out organizing assignments, or keeping things in order. In general though, if there is any way in which I can help with other duties, then I will gladly do those too. 
Also, I feel that my work at your department and course will be valuable for me on my resume, and just for general growth and experience.
Can't wait to hear from you.