Hello there, are there any good resources on how to start implementing using embedded-hal? I can't find any on the github page. I'm completely new to rust embedded development and came here because I want to use an RC522 (RFID reader) with my Pi5. I found [this library](https://docs.rs/mfrc522/latest/mfrc522/) which says: 
```
// Use your HAL to create an SPI device that implements the embedded-hal `SpiDevice` trait.
// This device manages the SPI bus and CS pin.
```
and now I'm lost. I guess I don't even understand the basics....
I got an LED to blink, some buttons to work and understand some basics when using RPPAL, but now I wanted to get an RFID reader to work (to try something more advanced) and this isn't supported by RPPAL. Instead it seems to be built directly on embedded-hal using SPI. 
Is there some beginners tutorial explaining the concepts etc. for SPI + embedded-hal?