Deleting portions of Audio with Audacity

Hello. I am a fairly new Audacity user, using it for my Podcast. When I bring in a WAV file, I seem to be having some problems with being able to delete portions of the audio file. If I do not listen to any of the audio and chose a portion to delete this seems to work well. But if I listen to some of the audio and then try to delete a portion, cannot delete. Can anyone let me know what I must be doing incorrectly, thank you. Tony

Edit commands (and most other functions) are only available when playback is Stopped (not Play, Record or Pause).
Press the Stop button and see if deletion then works.