Hello! Budapest is a fantastic city so you have a lot to look forward to! I wrote an article a while ago about the top attractions in Budapest, so you might find that interesting (http://www.hungarybudapestguide.com/budapest-best-best-five-budapest/). The most important is to taste a lot of the local cuisine and local drinks, to swim in the hot springs (Szechenyi Thermal Bath is the best), and to enjoy the panorama along the Danube both during daytime and nighttime… Enjoy your stay!