There's plenty of examples and exercises, plus an entire chapter dedicated to regular expressions.
https://m.youtube.com/watch?v=43BNFcOdBlY
In an afternoon, you can learn enough to be more than dangerous.
The presenter drafted up a set of (easy, yet practical) companion exercises and a pt2 video with his own answers. I cannot recommend this talk enough.
Although I hadn't the opportunity to put the knowledge to use and have since forgotten it (i don't work in tech), i find comfort in knowing i can reacquire the power of awk even sooner than the already-short first time around.
https://www.gnu.org/software/gawk/manual/gawk.html
The manpage alone is quite useful, though lacks some useful details.
The awk FAQ provides general background, including diffeerences between implementations:
https://ia802309.us.archive.org/25/items/pdfy-MgN0H1joIoDVoI...