You should first install the patch as Matlab R2019a break compatibility with the blockst V3.44 release.
The latest patch is available from the top thread in the Matlab forum section : https://www.microchip.com/forums/FindPost/1070708
To use this modle based design tool, you need to drag & drop the Master block into a simulink model. This will force all model settings required for code generation.
Chip selection is done in this Master block.
Clic on the "Build" button will then generate code, Compile and download it on your target.
(you need a compiler installed, either XC16 or XC32, as well as MPLAB X IDE which is used underneath to flash the chip).
The tool targets Chips (~200) rather than board. Thus you can use any board equipped with a supported dsPIC, PIC32.
You might use a Microstick II board, and connect it to sensor/actuators to test.
Few other board reference are listed in that thread:https://www.microchip.com/forums/FindPost/878432