This document is a practical guidance to help users in applying UBL customization and creating of UBL Use Profiles for specific B2B contexts. UBL is a horizontal standard; this means that it is cross-sector and aims to cover a generality of processes and data. If this approach allows UBL to be able to be adopted in many and very different scenarios and business contexts, on the other side it can make difficult and expensive (in terms of costs and times) the adoption because: - the size of UBL specification is bigger than what really be needed in a real framework; - too generic specification can be ambiguous. Applying customization helps to resolve the first problem and defining Use Profiles sorts out the second one. So, this guideline aims to provide a methodology to customize UBL and define Use Profiles; this favours and simplifies the UBL diffusion, increasing the efficiency of enterprises making business.