-The desert that stretches outside the oasis is a danger zone. Here, exploration will take place across the desert.
-In the Dead Dunes, you can undertake quests from the inhabitants of the oasis. Within the oasis you can chat to the inhabitants and listen to their stories, as well as buy items from the shops.
-Items used for battle restoration can be found in treasure chests, as well as purchased through shops in town. Stamina can be restored by visiting an inn or even eating a meal.
Thanks to FXN for the information.