I would start by learning rust at a user level via the rust book to get you familiar with the language without the extra layers that embedded systems tend to add on top of things. Keep in mind that the embedded space in rust is still maturing, though it is maturing quite quickly. However one of the biggest limitations ATM is the amount of architectures available - if you need to target one not supported then you cannot use rust ATM (though there is quite a few different projects bringing in support for more architectures).

If you only need to use architectures that rust supports than once you have the basics of rust down take a look at the embedded book, the Discovery book and the Embedonomicon. Then there are various crates for different boards such as ruduino for the arduino uno, or the rp-pico for the raspberry pi pico, or various other crates for specific boards. There are also higher and lower level crates for things - like ones specific to a dev board and ones that are specific to a chipset.

Lastly, there are embedded frameworks like Embassy that are helpful for more complex applications.