Petr,
Most counters in National Instruments' products have the counter separated in groups of 2, so that is why they use that counter and counter-1 notation. Since your board only has 2 counters then the counter numeration is just counter = counter 1 and counter-1 being counter 0. About the signal routing for pulse train generation you should not need to do it externally, the signal can be routed internally. Depending on the software this should be done automatically for you as soon as you setup a finite pulse train generation. I hope this info helps.
Regards,
Gazoo!
