I cannot change my audio from stereo to dual mono, please help!

I have an audio file that heavily plays out of the left channel. I can select my file in the timeline panel > and select 'audio channels' > but when the 'modify clip' tab opens I cannot change the 'Preset'.

Another user who was having this issue was told to move the 'Essential Sound' folder onto the desktop. I tried this, but nothing changed.

I have attached two photos. One is of intrustions on how to change the audio to mono and the other is from my premier screen. You'll notice in the instructions they are able to select the preset, however mine is grayed over and non-selectable.

I am very new to premier pro so I wouldn't be surprised if I was just making an obvious mistake, but any help would be greatly appriciated.