If the suspect is still present you should call the police on 999. If the suspect has left you should contact Police Scotland by dialling 101 who will take crime details over the phone. You should know the time or times it happened between and the size of the window smashed.
If the house is a private house you should take steps to replace the glass and secure the house. The police cannot recommend a glazier but they are listed online. If the house is a council house then you should contact the council to repair/replace the window.