first thing first,
call them and ask them not to wash your car, i received mine and founds loads of swirls and one big isolated scratch on the hood. paid 30k for detailing but scratch is still there, wont go.
here are the main things you need to do.
1 - inspect the body paint from all sides, doors, hood, roof etc etc. make sure paint is spotless.
2 - check door locks.
3 - check power windows, sunroof, all lights, indicators, wipers, infotainment system, seat reclines. MID, meter, signals, steering buttons, seats.
4 - check all the accessories including manuals, remote, tools, 2 keys, nav card.
5 - open the hood and start the car, listen for any odd noises. if found any dont accept delivery. also check all fluid levels.
6 - sales guy will make you to sign delivery documents asap so take your time and only sign it once you are satisfied with each and everything.
these are few main things. i might have missed some but primarily these are the things you should look for.
Allah naseeb kare amin