Hello Paul,
Unfortunately a class with the same name but different implementation has been defined in Mbed OS 5 ("/mbed-os/drivers/internal/LinkedList.h"). To use Sam Grove’s “LinkedList” library, once pasted into your project try to rename the class and the associated files to something else, for example “LinkedList_SG”. Also remember to modify the “main.cpp” accordingly.
As an alternative solution, you can try to use one of the containers available in the C++ Standard Template Library. For example “Deque” or “Vector”.
Best regards, Zoltan