I never changed pads on this model brakeset from Modolo, which has a different means of anchorage to the caliper arms thsn the higher model brakesets, but ai th8nk thisvmoght work.....
Slide the new brake pad into the holder so it almost hits the bolt head in the channel of the holder. Then, using a small flat bladed screwdriver, lift the leading edge of the brack pads by levering it up with the screwdriver tip so it just clears the top of the bolt and slide the pad over the bolt head while making sure the leading edge pad does not pop off the holder. The pad should settle down on the holder when the hole on the back of the pad lines up with the bolt head, once it is fully slide into the holder.
if you can clamp the holder on to a bench vise to do this, it will be much easier.