Hydraulic pressure is applied to the 2nd clutch, then the 2nd clutch engages the mainshaft 2nd gear with the mainshaft.
The mainshaft 2nd gear drives the countershaft 2nd gear and the countershaft.
Power is transmitted to the final drive gear, which in turn drives the final driven gear.
NOTE:
Hydraulic pressure is applied to the 1st clutch, but since the rotation speed of 2nd gear exceeds that of 1st gear, power from 1st gear is cut off at the one-way clutch.
The illustration shows the 7-position transmission; 6-position does not have the sub-shaft and related parts.
or 
Position in 2nd gear and 
Position
