Slowing time to key prompt

I am a beginner with Unity 3D with minimal experience. I have a game concept and I am trying to figure out the ways to make my ideas work.

What I will be doing:

In this situation I would to have the player character run towards a railing in order to vault over it. A particular key being pressed will result in vaulting the railing. When the player character reaches a certain close distance from the railing I want time to slow (maybe even a noise or something as indication) for a second or so for the user to hit the button corresponding with the vaulting action.

What I would like to know: How, if not to much of a hassle, would one get "time to slow down" for the button prompting and return to normal speed and lead into the resulting animation for the vaulting of the railing?

If you want the whole game time to slow down, set Time.timeScale to whatever speed you like(0-99.99). Default is 1.

If you just want, let's say, the character to slow down, you'll have to make your own speedFactor= ~1; variable then multiply any time-related movement by your private speedFactor.