Fernando Robert Yu
The official rules are in the files section. Why not read the rules if you want to know how the game plays? It isn't exactly like any other game, really. It is much lighter than the vast majority of other games you mentioned.
I agree with Todd's comments. SA maybe too light for you, UNLESS that is the type of game you are exactly looking for (ie a lighter euro in between the heavier games you just mentioned).
It's either this or Lords of Waterdeep for this particular niche, although lately I have found Glen More to be another light euro (although it is a Rondel and Tile Laying game rather than worker placement)