first of all, to load a new account system is not that difficult.
you can just modify the three first columns in the accountingUS.xls that comes together with compiere, creating a new number for your accounts, new names and descriptions.
so far, so good. you load the csv as you would do with the american one.
for each document and for bank accounts and bpartners there are default accounts. those are defined in the 8th column of the xls.
you can try and and assign those tags to the accounts you need. if you have any doubt towards which account does what just let us know.
the last part is the most difficult one. a series of doc_*.java are the source of the transactions. each of them has a commented description of the posts created in each case depending of the document chosen.
i hope this serves as a brief explanation. let me know if you have further doubts.