After 8 years of being a SAP Business One (ver 9.0) user in which I was the main administrator for Item Master and Bill of Materials, I was a main member of re-implementing to version 10.0, especialy in data migration and cleanup during the last year...
As Matija mentioned, SAP learning journey chapter quizes are very simular to the test. That is how I prepared for my certification which I earned last September.
Business Partner's 'withholding tax %' is a column of the OCRD table. Try :SELECT Cardcode,CardName,DdctPrcntFROM OCRDIf you need 'Withholding Tax Deduction Group', that is DdgKey which is link to ODDG
Arkadiusz,You can get templates from the DTW software that SAP provides with SAP Business One. Here is a link to a blog on how to obtain one. https://blogs.sap.com/2014/05/23/generate-dtw-template/