How can i create a code that "boost" the player horizontally

Is there any way to boost a player horizontally with the press of a button eg."c". im making my game in 3d and can't find any tutorials to help.

 

You won't find a tutorial that covers every single feature that you can imagine. Rather, you want to learn all of the basic engine functionality and then you'll be able to figure out how to solve all of these problems on your own. Actually, this should cover everything you'd need to implement this feature:

https://learn.unity.com/project/beginner-gameplay-scripting