Import track sound

Hello nauts,

I went over the manual + looked around in youtube and couldn’t find how can I upload sounds to the Track Sound (Not Sound Browser), so I can trig different sounds within a track.

Just to make myself clear, when I press a trig and turn the data knob, the above screen comes up to allow me change that trig to a different sound. How do I upload sounds to this list?

Many thanks in advance, Ita