I just did import the example project. The “stm32746g_discovery_ts.c” and the “Components” directory (maybe other file for more features) are also missing from this example project.
To add “stm32746g_discovery_ts.c”, on your project, in Drivers\BSP\STM32746G_DISCOVERY, in the menu, click on New > File > Advanced, check “Link to file in the file system” then browse the “stm32746g_discovery_ts.c” file from the firmware (which should be in ....STM32Cube_FW_F7_V1.1.0\Drivers\BSP\STM32746G-Discovery)
To add the components, just copy paste the components directory (in ....STM32Cube_FW_F7_V1.1.0\Drivers\BSP\Components) into the project, in Drivers\BSP
Hope it solve your problem.