Below are the main symbols used.
The action starts at 11.12
Custer has five troops: F (Yates), E (Smith), C (Harrington, L (Calhoun) and I (Keogh)
Reno has three troops G, A and M
Benteen has three troops D (Weir), H and K
The Pack train, escorted by B troop, is in two parts