Go to Effects -> Audio Effects. Here, you can use a mix of "New Blue Noise remover", "New Blue Hum remover", "Denoiser" and "New Blue Noise Fader". I have used them with really good effect for enhancing human voice and suppressing the background noise during recording. What they effectivelly tend to do is to reduce the human voice volume. That you can increase by increasing the "Audio Gain" by right clicking on the clip on timeline (Expert mode) and selecting the Audio gain for the clip in question.
Check if this helps.
Please excuse the question, but I did not want to take anything for granted.
Your specifically asked:
How do I remove a noisey audio in a video in elements 12?
Are you asking how to remove noise from an audio linked to a clip with audio linked to the video?
Or, are you asking how to get rid of the audio portion of a video audio clip where the audio is unacceptable because of noises?
If the latter is your question, right click the video and select Delete Audio. There are other ways, but that is the quickest. Then you can import alternative audio if that is what you want to do.
Please review. We look forward to your follow up details.