In order to trigger pads, your midi controller needs to send MIDI note messages – not midi CC messages – this is 99% of the time what the problem is with midi footswitches.
You can often use software that comes with the footswitch to configure it to send MIDI note messages. Unfortunately as I don’t own any footswitches, I can’t provide instructions but hopefully the manual that came with your pedal should help.
If you’re struggling to connect a MIDI device, I recommend this article: https://www.koalasampler.com/help/midi/my-midi-controller-isnt-working-with-koala/
A bit more explanation: There are many kinds of midi messages, but 2 of the most popular ones are note messages and cc messages. Note messages are usually used for playing notes, samples, pads whatever. CC messages are usually used for changing values of parameters and knobs. But for some reason, many footswitches default to CC messages. Some you can’t even change from CC.
If you’re still struggling, please get in touch with me at https://www.koalasampler.com/contact