Hi Daniel,
Welcome to the forums!!
I can definitely agree with you on some of the product pages, once someone stubles upon them the Core guys are super quick to add as much as they can to them though.
Imo I think thats where Core sets themselves apart from other electronics stores, on the forum there is a ton of help about all of the different parts they sell. Being said that is also the nature of the hobby, sometimes you’ll hit a roadblock with a particular board or software implementation.
From the looks it it there are some jumper wires that come with the product, but if you were making a PCB to go with it an IDC cable would be your best bet to plug in (not sure if this one is the right pitch).
Most of the time libraries or API’s are pre-written it interpret protocols such as I2C, SPI, UART, (depends on the devboard, it looks to be implemented on the Teensy but only with one channel).
The link takes you to DFrobots website, its the brand that Core has this one under, they have some neato boards at a good price, but not quite the documentation like PiicoDev, Adafruit or Sparkfun.
I found this on the K210, looks to be a super juiced up MCU: https://www.seeedstudio.com/blog/2019/09/12/get-started-with-k210-hardware-and-programming-environment/
I’d definitely be keen to see this board fleshed out as well, I’d imagine @Donald23173 from this thread would love to see them as well!
PS: For a higher price you could also try Seeed’s multichannel mic, while the price is higher it offers driver free installation (not sure if an RPi will support it out of the box)
EDIT: just came across this devboard featuring the K210: https://core-electronics.com.au/maix-bit-ai-development-board-risc-v-k210-iot.html