Make sure you import the latest version of Mobile Controls and the First Person addon
Download the following file and extract its content inside your project, it contains a prefab and its meta file. It is a prefab variant of FPCamera, it should pick up the prefab connection automatically.
Assuming you are using the default HECorePrefabsMobile (asset referenced from the HECore in your scene), assign the FPGameManager to the GameManager variable and add the imported prefab FPCameraMobile to the CustomObjects list.
If you have your own HECore asset (skip if not): simply assign the GameManager and the CustomObject to your HECore
If you have your own GameManager prefab (skip if not): Make sure the FPCharacter or a derived character is added to the Characters list
