with their ex-human memories I think.... As they comes back to the place they used to go when they're still alive or a place they usually go or hang around (or live-in).
PS.if they can smell the scent would it be a bad smell or nice one ?
It's not scent...
A Zombie is still just an undead human so unless he was blind prior to turning his sense of smell would not be heightend.. remember they have not become zombies and suddenly inherrited an animals sense.. they will have the same senses they had in life... only difference now is they've lost their humanity... Stand in a pitchblack room with a couple of friends.... how do you detect where they are.... unless you have a particularly pungant friend you won't be able to smell them,,,, yo will hear their breathing and be able to detect movement by the sound of foot steps and possibly a slight draft... so i say humbug to the smell.... do the same with the lights on... you will see them before you smell them... a zombie would sooner recognise the scent of a dog or cow than a human because as humans we do not rely on our sense of smell to interact with people but we do recognise the smell of a dog thats been on the sofa or whatever...
Zombies hunt by sound and sight. except stevie wonder he can smell you ....
Now the next stage.... they're are basically instictive.... so althought they can't learn on an academic level... BUT... (as much as i hated land of the dead) anything working on instict has the ability to improve it's insticts learning slowly and very basically.... so if a zombie found lots of yummy humans in a specific place they will keep returning to thats place It's hunting ground... until all available food sources are gone.. then it will search again... it wont follow a trail like scent.. it will just search... until it finds something it can eat and make that place it's new hunting ground and so on
my research indicates that the deep sunken eyes of zombies are incapable of seeing,
hunting is done not by scent but by feel.
zombies emit a strange liquid from cuts and scrapes that accelerates in middair, bouncing off available surfaces and making theyr way back to the zombie.
the zombie feels where they've been and what they've touched, human flesh being the most recognisable
if zombies lose such basic senses as sight then how can they perform complex tasks like zombie eco-location? they are people, nothing else. eye sight may diminish but not to the extent you say. nice theory though.