the shapefile specification is here https://www.esri.com/library/whitepapers/pdfs/shapefile.pdf
the shape field will contain the multipoint geometry to which one attribute in the dbase file is associated, hence, the multipoint designation, multiple points to one attribute
There are numerous threads on dbase format on the web dbase IV I think is the one being used, so you might query those as well... for example... http://www.dbase.com/KnowledgeBase/int/db7_file_fmt.htm
rather than reinvent the wheel, you might want to look at some packages that do it already ... ie for python pyshp 1.2.3 : Python Package Index
And there are builtins that can be used within arcpy to generate multipoints and export attributes out to shapefile format if you need. those