From the main Feed, tap the 'Performance' tab, then tap 'Rounds' and select the round to edit.
Once within the 'Round Summary', tap the 'More icon' (3-dots in the top-right) and choose 'Review Round'.
Then you should be able to scroll through the holes and make the necessary edits and additions before saving your changes.
Press the 'More button' on the bottom of the screen and 'Finish Review' when you're done.
Note: If you used Advanced Input, you can see all your tracked shots. To edit any shot(s), tap on the circle icon of the appropriate shot number. When editing and adding shots in Advanced Input mode while off the course, make sure to turn GPS Mode 'Off'.