Slicing for 2nd extruder

hello,

ive a problem with my slicer. ive loaded red filament on extruder 2 and black filament on extruder 1. i want to print a piece in red so when i place it in the reptier software and select extruder 2 it will print it with extruder 1 when i slice it.

how can solve this?

In the Slicer tab, select Vertex single extruder under Print configuration.

The problem is solved, thank you