Simply load up the map 'Papu's Pyramid'. For the first jump you must do a trick jump to reach the shortcut (took me a few tries) and the second one is simply a normal jump but timed right and is straight after the first shortcut. The trophy description states that it only has to be done in the same race and not lap so no stress to emulate them one after the other. I did one on the first lap and the next on the second lap.
I created this video to help:
Hope this helps: