We Define the Extruder number in PCB named E1 E2,
but make attention about that, in the repetier web configration page you need think it as E0 E1.
Refer to The heater number is H0 H2
Refer to The Temperature number is T0 T2
The H1 T1 refer to the heat-bed
you can open the heat-bed fuction in configuration.h