Keep my character moving at all times

My game is an infinite runner, and i want my character to always be moving up the x axis. Tapping right, its a mobile game, will cause him to speed up, tapping left will cause him to slow down. I don’t know how i can do this though, because i don’t see a minimum walk speed, and Setting his physics linear velocity doesn’t seem to be doing anything. Help would be much appreciated.

You can do it with “Add Movement Input”. Else, you have a tutorial here to make a “basic” Endless Runner :

Hope it will help you.