The problem seems to be that you recorded multiple clips in one single track. MixPad can only export:
1-The entire project
2-Single or multiple tracks. You can export multiple tracks at once
3-Single clips. You can do it one by one
Now, if you wish to export every single clip you have on each track, you will have to do it one by one or you can move your clips to new tracks, so that each clip is on its own track and then, go to Export > Export Individual Tracks > tick all the tracks you wish to export > select the destination and Output File Type > click Export.