When I did all the work on my car I had the battery disconnected and needed it locked, and yes it's just a case of locking the car, I think with the boot open and disconnect battery then close the boot, iirc if you lock the car with the boot closed then open the boot and disconnect the battery the alarm will start to go off on its back up battery, it's one way or another, but you'll know it's wrong as as soon as the battery is taken off it'll trigger the alarm.
As mentioned above, make sure the key lock works first otherwise you'll be right up poop creak, it is fairly stiff and could do with a bit of lube just to help it along first of all.
Just for reference, I don't have a parasitic drain and my car can be parked for a month and still start fine, I do have a massive yuasa battery fired though but it holds charge for ages.
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