You can find the information regarding MPS2+ and MPS3 from below link：
For the fpga images and related application notes documents on MPS2+ and MPS3, you can find them as below:
Currently, the M23 example is not provided for MPS3 board.
If you want to use M23 example, you can use it with MPS2+ board, the example is AN519.
AN519: Cortex-M23 IoT documentationAcceptance of a EULA is required before download