Cannot cut selected audio within an audio file

So I just downloaded Audacity and want to use it to cut a part of an audio file(.wve)
However after I select the part of the audio I want and do Edit > Remove Special > Trim Audio as the tutorial said
I was unable to select it (the button was grey)
I hope that you can tell me what the problem is ASAP
Thank you

Check that playback is stopped and not just paused (click the “Stop” button).