how to generate/read a glyph in ocr?
This is addressed in the relevant information you quoted, specifically in the following sentence:


  Each stimulus was converted into 16 primitive numerical attributes (statistical moments and edge counts) which were then scaled to fit into a range of integer values from 0 through 15.


Many machine learning algorithms won't be successful with the raw raster data, instead requiring features such as the 16 "primitive numerical attributes" mentioned above. (Deep learning algorithms should work correctly with the raster data, though.)

Computing these numerical attributed is a one-way process: you cannot recover the glyph from its statistics. We compute these statistics since we think they are the salient features which distinguish one letter from another.