How to change prefab height

[scotth1701]

I am trying to make my first map.

I'm basing my map on a real world city. I have picked a 4 way intersection as a starting point. In real life it is 15m above sea level. How do I set this?
And for example 3km north of this intersection the road has gone down hill to 10m above sea level at another 4 way intersection, how do I set this new height?

I want to make a city 4 way intersection. I have made the road height 15m above ground as it will go down hill in one direction further down and up hill in the opposite direction further up. Anyway at this intersection the roads are at 15m how do I change the height of a frefab crossroad to 15m to match the roads so I can connect them?

[PaZz_]

The middle "Position" value in node properties (hotkey 'N') determines the height of any object. For changes applying to a prefab, the origin node (red square) must be selected. Otherwise it won't have any effect.