Once you purchase the product you will have Horse.zip file. Extract it to your desired location then you can open Horse_high and do whatever you want to do.

You can also import the obj or the fbx file into another 3d package softwires like maya, cinema 4d and others.

You will also find a folder named textures which contains all the texture of the horse model. The textures are 4K so  that you can get better quality.