That sounds like it could be a pretty big task. If you're just learning, then I'd recommend Blender. There are tons of resources out there to help you learn Blender and the program itself has many powerful features that GMax lacks. It may also be easier to texture with as well. However, I'm not here to put one in front of the other. It's just my recommendation and I think both are suitable for what it sounds like you are trying to do.
If you have access to the Google Maps and/or Trimble map servers from your apparent location within China (some may not have this access for reported reasons arising from national policy), you may also wish to consider learning this process using Sketchup.
The use of Sketchup version-8 32-bit is allowed for either personal or commercial purposes; but use of a Sketchup version subsequent to that (ex: 2013, 2014, 2015, 2016 etc.) reportedly requires a commercial license for any commercial use.
The Sketchup "Geo-location" feature allows access to top-down views of the same aerial imagery seen in Google Maps and/or Google Earth; this feature also permits one to download that Geo-referenced imagery (and its associated terrain mesh) directly into a Sketchup project.
One can then draw the outline of building footprints, and 'extrude' them to the desired building height.
In areas where Google "Street View" imagery is available, one can select a face of a building, right-click, then choose "Add Photo Texture" to select a local Street View image of the actual building one is working on.
In some areas, "Bird's Eye" views are also available to allow access to additional images of the sides of a building which do not face the street; some may find this useful for texturing a building on all sides.
You may wish to view this tutorial by Aidan Chopra via YouTube (if accessible from your Geographic location):