C major first — the trumpet's open-horn key. Each scale drawn as a path of fingerings.
root (written)
scale
practice
C'
open·p2
D'
1+3·p3
E'
1+2·p3
F'
1·p3
G'
open·p3
A'
1+2·p4
B'
2·p4
C''
open·p4
Watch the fingerings as the scale climbs — that's the path through the grid. C major sits easiest because so much of it falls on the open horn; that's why it's the trumpet's home key.