When Kate leaves the yurta, proceed towards the bottom of the screen, amongst the ostriches. When you reach the caravan, got left and proceed down the sand way - leaving the small, beige building behind you on the left.
Having gone past it, go towards the sheer riverbank - you have to walk around on the left the place reminding a furnice with four chimneys surrounded by dark stones. You will se Kurk there - talk to him. Kate will promise to go across the bridge and talk to a Yukol guardian living on the other side.
Then go to the building you've just went by - it's the local checkpoint (or whatever they have in Siberia instead of these). Approach the window (on the left, next to the bridge) and talk to the guard. He will allow Kate to cross the bridge if she manages to get the mill wheel going. (If you want to get Anything goes achievement then you must lower the water mill's wheel into the water before you speak with the customs officer - you get this achievement in the moment when he speaks about this subject).
In order to do that, go to the other side of the building, where the terrace is - at the very end of the building is a metal ladder - use it to go down. On the terrace below go back a bit and use another ladder to get below.
When you're there, click the big lever (on the right, shown above). Kate will manage to pull it. Go back to the guard - inform him of the success and go to the bridge (left of the building). Run through the first part of the bridge, then the other part - the guard will raise them.
Behind the bridge go towards the wooden fence (on the right) and talk to the Yukol guard. You will learn that the ghosts require special smoke signs and... some vodka. Leave the yurta and go back the bridge onto the other side.