Looking for a furnished 1-room flat or a room in an apartment

Hi, I'm Idil! I'm 23 years old and from Istanbul, Turkey. I study Applied Biology in Hochschule Bonn Rhein Sieg and will be starting my 3rd semester. I'm looking for a place in Bonn close to Hauptbahnhof since I will be traveling to Rheinbach almost everyday for my lectures and lab courses. I lived in a dorm for my first year but would like to move to a better apartment since my dorm room was very tiny.
I'm an easygoing and hard-working person, and I'm also very social. I love listening to music and working out at the gym. I aspire to be a scientist working in a lab and to work in the field of genetics.
I will be flying back to Bonn from Istanbul on September 28th and I'm hoping I can find a place to move in until then.