beginners project help

Hello,
I am trying to find a home automation solution that will enable me to the following to start with. I did consider a Raspberry pi with OpenHAB but think I would struggle with the coding. Is there a product and or interface that would easily let me do the following using my pi? Thanks for your help :)

I want to place a motion detector outdoors on the rear of my property that turns on an interior light if an intruder approaches. i only want the light to stay on a set amount of time. I want some control of when it is active and not active, like only during the hours of darkness for example.

p.s i learnt html years ago when the internet first came about and built a basic website so i will be able to learn basic commands just daunted by all this stuff id have to learn for openhab whilst im older and not as bright

Thanks,