For fishing you need to use the crank which will definitely be more awkward since you're on the PC. Basically you need to crank to keep the fish icon in the right inside the zone for a long enough to fill the meter at the top. If the fish is outside the zone then the meter progress you made slowly decreases. If it's still unclear you can lookup the fishing mini game from stardew valley to understand it better
I think there may be a problem with the walk away option so I can definitely take a look at that, at least you won gold lol.