how to get from memory X and Y positions

[jetcar]

i was looking how zoomhack works, it looks very simple but i don't get it how to compute IntPtr and offsets. I can find position variable in game using cheat engine, but that is changing every time i start the game. I want to write bot which can use coordinates to move from one point to another while using some aoe skill i think it will be very useful on non generated maps. If it is possible to catch position then just run one time through the map while saving positions and then just run bot using file with coordinates.