Roger Harvey has produced a comprehensive video course of progressive lessons on how to arrange for brass designed to help aspiring, or improving arrangers to develop this really useful skill.
It is in four parts:
1. Transcription Plus
(starting with very simple transcription and developing options to take account of technical concerns)
This section also has a range of resource videos to cover technical essentials and some elementary theory
2. Keyboard Transcription.
3. Orchestral Transcription
4. Free ArrangingFor more information follow the link: