I refer to the same place in the manual.
"A positive current flows when the applied voltage for the left electrode is higher than that of the right one. A positive current corresponds to the flow of charge from left to right, meaning that the flow of electrons is right-to-left (since electrons have a negative charge)."
Electrons will flow to the terminal with highest voltage, i.e. the current goes left to right (this is the flow of charge), but electrons go right to left, in this case of higher voltage on the left electrode.