In 1st Gear

WARNING: This page is about a different car, the 2008 Acura TL and 2007 Acura TL. However, it is still accessible from the selected car via links, so may be relevant.

Hydraulic pressure is applied to the 1st clutch, then the 1st clutch engages the secondary shaft 1st gear with the secondary shaft by the one-way clutch.
The mainshaft 3rd gear drives the secondary shaft via the countershaft 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: Identifying Power Flow - 1st Gear
Courtesy of AMERICAN HONDA MOTOR CO., INC.