You can get a plug and play harness for about 10 quid and all it does is take power and split the ignition power harness so the relay for the timer keeps the car running for the set time
And yeah you put one of the wires to hanbrake switch so it only works if handbrake engaged.
All the diagrams are on net if you don't get instructions and really easy to fit mate.
You wont get the a/f meter reading correct as they work on narrow band and scoobys are wide.
Or something like that