I am just worried as i will be using it on road for a while before i go off-road again. I don't want to go flying over a car with bike still attached
The only advice I can give is just get some pedals and shoes and go for it.
Start off with the tension set low and ride somewhere like a park or a field and practice clipping and unclipping lots, and obviously, do this with both feet. Just keep doing it until it starts to feel natural, which, if you've only ever ridden with flat pedals and with no toe clips and straps might take a little while. Practice unclipping and re-clipping on the move, like you would have to do for a quick dab on a rock or something.
I'd bet you'll find that it's nowhere near as hard to get used to as you thought.
Once you get more confidence then you'll probably want to increase the tension a bit, as in my opinion too low a tension is at least as bad as too high, as you'll unintentionally pull your foot out on the upstroke or even on bumpy sections of trail when you least need (and expect
As far as setting up the cleats on your shoes goes - you want to pay attention to the angle that your foot naturally adopts. Sit on the edge of a table or high stool and just let your feet hang naturally and check whether one or both face in or out . If so, you need to fix the cleats to reflect this positioning.
Cleats further forward generally let you spin better and further backwards might give you a little more power and maybe will make you feel more "in" the bike when you're out of the saddle on technical stuff and drops. Directly under the ball of the foot is where I'd start and work from there.
BTW, every time that I've collided with something or crashed at any speed I've never stayed attached to the bike - we've always gone our own separate ways