Intellisense c023-203 alarm. How do I use it???

Hi I know this may seem really dumb but I have no one else to ask. I recently moved into a property that has an alarm fitted (says intellisense c023-203). The previous owner left me the code but no manual or explanation on how it works. Can some one please help. How do I set it to come on at night? When I’ve tried it just makes a loud sound for ages until I eventually have to turn it off. I would like to have it on at night times and then also set it when I leave the house 

It may be the same as this alarm, but do check it is programmed the same; mostly they are rebadged as is but sometimes there are minor changes.

View attachment CK-800l-Intruder-Alarm-Panel-User-Manual.pdf