Here is the reality check. You will find many sketchy websites claiming to offer the "David German Festive Trumpet Tune PDF" for free. Be very careful.
Most of those "free PDF" sites are either: david german festive trumpet tune pdf
David German’s work is primarily published by Lorenz Publishing Company (specifically under their Sacred Music Press or Beckenhurst imprints). Here is the reality check
Week 1 — Foundations
Week 2 — Rhythmic and stylistic shaping David German’s work is primarily published by Lorenz
Week 3 — Ensemble and polish
Musicnotes specializes in digital sheet music. Their interactive app allows you to transpose the piece instantly and even play back the MIDI. If you need the piece for a B-flat trumpet but only have the C version, this is the best option.