Hi,
the board that you mention sadly does not have a runtime 
It should be relatively easy to port the runtimes since we already have a few STM32F4 devices but that would be a bit overkill for a beginner project.
I suggest either getting yourself a raspberry pi pico and following Jeremy Grossers Pico Guide (this option is a lot easier) or following AdaCores Guide on running bare metal Ada for any cortex-m chip (this is harder because you will have to read through the chips documentation)
I have done both and suggest the pi pico method. The documentation is great, there are a few runtimes already and you can start right away programming with other peripherals. The barebones cortex-m method is great if you want to learn and understand how the chip works under the hood. (You can actually feel how well Ada was made to be used on embedded platforms!). Keep in mind tho that you will not be able to use Adas tasking system unless you port the Ada runtime to support it.
Edit: A small blinking led example I wrote using the cortex-m method for the STM32F303. As you can see I wrote the “wait“ methods myself (had to read through a lot of embedded timer documentation and how my chip handles it)