No sound at all when playing sample

HI all just upoaded the cubase 9. got the program with an interface i just purchased. uploaded it all seems to work , it didi crash on me 2 x. so when i go into production and play back what is already on one of the tracks and no sound comes out of my speakers. I go into VST connections and it is saying my speakers are missing ? would I need to hook up external speakers ?