In the quest "The White Dragon", the path of which is revealed in this part of the Guide Monster Hunter Stories, you will have to climb on the big tree of Babda in order to recover a dragon egg.
After activating the quest, leave the ruins by taking the path on the left, then start climbing the big tree (picture1). When you reach the second level, a Zinogre will attack you (picture2). To defeat this creature, start by getting rid of the insects that accompany it. Then try to counter his attacks with technical and speed attacks.
At the end of the fight, resume your ascent of the big tree to finally reach the top (picture3). There, approach the egg to trigger a cutscene and end the mission (picture4).