not seen a guide as such , its fine for having a look at the database , and seeing whats in it
but to work with heroes db i would really advise using microsoft access . i rarely recommend anything by miscrosoft but access makes it much easier for working with
in the database using access u'll find 4 tables , 3 that are in use are Monster , Magic and STDItems , another there is 'ffsd' but ithink that was just one for messing around with, does nothing that i know of for game
each of the 3 databases had different columns , most as easy to make sense of
like monster has fields for exp/hp/damage/movespeed/hitspeed /looks , all them are simple to change as required
items has similar stuff , set ac/amc/sc/dc/mc/lvl etc
magic gets a little more harder tho, beyond power of spells and lvl required changing them needs thought and testing
the weird stuff starts to happen in Items under fields like stdmode , anicount and shape (not like looks)
rings / braces / neckies /armours / weapons etc have a number (or 3) set in stdmode , only certain numbers usable for those or they wont equip/repair/sell , and the ones with 3 possible number can make some other fields do different things
if u read the different merchant txt files for npcs in bw etc , at top for , eg , weaponshop it will read %100 +5 +6, meaning he only deals with weapon (stdmode 5 and 6)
in the entry also in itemsdb theres a field for 'need' and 'need level'
if need = 0 , then need level is simply level required to wear item
but if need = 1 or 2 or 3 , then needlevel becomes dc or sc or mc requirement