digital waveform frequency measurment

Hi,
i have Motor driver can give me the speed as feedback "digital waveform"
the frequency is proporational with the speed
i have Cdaq 9188
also i have ni9401
1. at which slot i have to connect the cmodule 9401 to be able to reach the counters ?
2. how i have to connect the speed feedback to module ?
3. can i have guide about this issue ?
thanks alot