Hi JCuer.2,
As X-NUCLEO-IKS01A1 is not supported and from what I can see, there is a big similarity between your expansion board and X-NUCLEO-IKS01A2, this is the reason behind my proposition.
Otherwise, you find linked the STM32Cube BSP drivers development guidelines, It details the architecture of BSP drivers (class, component, common and bus) and gives examples of implementation to guide you developing BSP drivers on a given board.
Here you find also the Development guidelines for STM32Cube firmware Packs ,the Development guidelines for STM32Cube Expansion Packages and the User Manual to create a software pack enhanced for STM32CubeMX using STM32 Pack Creator tool for more information about pack creation.
Please feel free to come back to me if you need any other information.
Khouloud.