In need of help (complete newbie)

Hi everyone! I was lucky enough to be gifted the Märklin Tracks, Train and Transformator shown below. As far as I understand it I need another Transformator to regulate the speed of the train. There are quite some sparks flying when the train runs. I decided to clean tracks and train with some denaturated alcohol. Feel free to roast me, open for any help tips and tricks! I want it to just ride around a Christmas tree (slowly). What do I need? What have I done wrong?