Very simple way to invoke FLAC (for encoding from WAV, and decoding back to WAV) from a simple GUI, without requiring updating your Environment Variables or doing anything else (other than
installing FLAC itself using the normal installer file):
install "FLAC Frontend"
Absolutely couldn't be simpler. Works perfectly.
Personally, I prefer a bit more sophistication and automation, particularly in the tagging department. So I use
Audiograbber (and have for 15 years) to create both MP3 and FLAC from my CD's. Works perfectly to invoke LAME or FLAC as the "external encoders", as well as doing the complete tagging for both based on data retrieved automatically from FreeDB. And of course you can edit the data retrieved from FreeDB before actually doing the rip/encode/tag using that data.
Either "FLAC Frontend" or "Audiograbber".