22 year old boy, looking for accomodation in Stockholm

Hello. My name is Alexander Iskantar, I am 22 years old student old from Greece and I will be performing my Erasmus traineeship at Karolisnka Institute starting from the 25th of September until the 5th of January 2018. I was looking for a room to rent For 3 months. It would perfect if the apartment is relatively close or if there is easily accessible transportation.

thanks in advance.