In 1st Gear and 1 Position

Hydraulic pressure is applied to the 1st clutch, then the 1st clutch engages the secondary shaft 1st gear with the secondary shaft.
The mainshaft idler gear drives the secondary shaft via the idler gear shaft idler gear and the secondary shaft idler gear.
The secondary shaft 1st gear drives the countershaft 1st gear and the countershaft.
Power is transmitted to the final drive gear, which in turn drives the final driven gear.

Fig 1: Power Flow - D, D3, And S Position
Courtesy of AMERICAN HONDA MOTOR CO., INC.