libiio has existed for many years and numerous training materials have been created. Here are some of the most popular:
Using the Linux IIO framework for SDR
ADALM-PLUTO and IIO Workshop
Using the Industrial I/O Framework for Easy Prototyping of Software Defined Radio (SDR) Transceivers
libiio - A Library for Interfacing with Linux IIO Devices - Dan Nechita, Analog Devices Inc