classification issues (specific and global)

i am trying to wrap my head around a couple things. 1. can anyone help me generally with when i need to make a determination on a classification? for instance specifically what are the names or the tables i would be required to do this? i would like to list these for myself. 2. i have the classifications and i have the descriptions of the classifications vis a vis the - well i guess these are “Uses”. so classifications are ASSEMBLY BUSINESS EDUCATIONAL FACTORY AND INDUSTRIAL HIGH HAZARD INSITUTIONAL MERCANTILE RESIDENTIAL STORAGE UTILITY AND MISCELLANEOUS then examples of business in 304 business group B would be a list starting with “airport traffic control towers” and ending with “Training and skill development not in a school or academic program” with the latter having a parenthetical clause too big to re-transcribe. and EACH classification has a long list. the ptobl i shears seems to have us there is usually some kind of architectural eye candy like chrome columns or curtain wall construction or something to distract me and then the USE is described in what feels like a mashup way. so instead of seeing “classification is “Assembly A-1” or “Business Group B” it says it is a frog dissection shop next to an automotive repair place. or a vegan fireworks production and sales outlet next to a open plan soto showroom. should i be digging into the code to see that in 304 business group B there is a listing fit “Motor Vehicle Showrooms” and then go down the list and see there is a listing for “Training and Development not in a School or Academic Program” and try to figure out if the frog dissection class should be in Business or Educational? anyway any recent testers understand how to work these better?