As a previous poster said, you need to 'select' the area of the track, or the whole track, that you want to apply the effect to, before Audacity will apply the effect.
In my experience, even the most recent stable version of Audacity (1.2.6) will NOT export a project as FLAC files; I detailed my experiences in a separate
thread, and someone recommended there that I export my project as .WAV files, and then convert the WAVs to FLACs with another software application. Considering that 'Export as FLAC' is an option on the first menu in Audacity, I thought this was .. unusual, to say the least.....
To break a large file into individual tracks, you need to create a 'label' track in addition to your audio track, then define labels in the label track at the split points. Then when you want to export the audio to WAV files, you select the 'Export Multiple' option, and it should output a set of files split as per your labels. I found the label track frustratingly difficult to master, but I'm getting there....
There's lots of instructional material at various sites that answers the above questions and much more; I found most of my answers by googling the appropriate keywords, and useful resources were usually to be found in the first page of google results.
Regards, Graham