Click the following link to watch a great video about how to configure your MIDI controller:

https://www.youtube.com/embed/W4ThdrIv9vc?feature=oembed

The same information is presented here in writing.

We're going to demonstrate the setup process using an M-Audio Oxygen, which emulates the Mackie HUI controller.
Start by checking to see if your MIDI controller offers a mode or emulation for the Mackie HUI. If it does, select it (see below).

• Press the Y key in Samplitude Music Studio to open the System Options.
• Go to "Hardware Controller" and open the "Controller Setup" tab.
• Select your controller.
  (You should no longer hear any sound when you press the keys on the M-Audio Oxygen 61).
  

Choose the following settings:

• "MIDI In": "Oxygen 61 MIDI In" (available if the Oxygen driver is installed; if it isn't, you should see "USB MIDI Keyboard" or something similar)
• "MIDI Out": "Oxygen 61 MIDI Out" (available if the Oxygen driver is installed; if it isn't, you should see "USB MIDI Keyboard" or something similar)
• Number of tracks: 8 (preset)
• "Output": "Send Echo"
• "Internal Mode": "Mackie HUI"

Important:  Click  "Save as..." and enter a name. Doing this will retain the #empty preset.

• Open the "Customize Controller" tab.
• Next to "Auto Increment", place a check mark in the box on the right. 
• In the "Program function" box, open the dropdown menu and select "Transport" (2nd option from the top).
• Click "Record" > "Learn" and press the record button on the M-Audio Oxygen.
• Do the same for all other keys on the Oxygen.
• After all keys have been assigned, click
  "Apply", followed by "OK".

More info
To watch a tutorial on hardware controller learning, click the following link:
http://www.youtube.com/watch?v=W4ThdrIv9vc

Do not change any settings except the ones related to the "learning" of the hardware controller.

For more information, refer to the "Customize Controller" section of the Samplitude Music Studio Help. To open the Help, press F1 in the program.