Rally point for produced units

[marconos]

Help please

Supposedly you can set a rall poin with Alt+RMB on the city bar, but I can 't figure it out. I want to have my main military production cities produce units and automatically send them to a staging area. Is such a thing possible? If it is why am I totally in capable of figure it out? (oh ya, and how do you do it)!!!

 

[Forkandles]

Left click the city.
Shift and right click the tile to be the rally point.

Profit!