Connect the MIDI foot controller to the MIDI interface with the appropriate cable. It will most likely use a standard five-Pin MIDI DIN cable, though some MIDI controllers include a USB port as standard, negating the need for a separate interface.
Power on the computer and launch the DAW. Set up an audio channel, and turn on the monitoring function, allowing you to hear the output of the channel in real time. Insert a digital delay plug-in into the channel strip, and test it by running some audio through the channel. Connect a microphone or instrument, and play through the selected channel. You should be able to hear the delay effect.
Engage "MIDI Learn" mode in the DAW, and highlight the delay unit's "Bypass" button. Click the first foot switch on the controller. This now is assigned as the "Play/Stop" control for the loop pedal. The "Rate" control on the delay unit likely has two forms of input: A rotary dial that adjusts a BPM rate and a selector switch that moves between different set quantities, "1/4, 1/2, 1Bar, 2Bars, 4Bars etc." Engage "MIDI Learn" mode again. Highlight the selector switch, and click the second foot switch. This switch now cycles through different loop lengths, relative to the BPM rate of the song.