How can I fix my 9427 alarm?

iv had new windows and front door fitted. We have had the house for a year. We have no instructions and the door chime don't work. The window firm tried to mend it but I have a loose red wire and don't no what order the wires go in and we need it working because we look after people with learning disabilities and if they go out off the door we Carnt hear the door going. The alarm is scantronic 9427 style.