Please give easy methods also because i am a beginner thx
Hey @Botspence!
You should be able to do so using splines. Check out the the following non-Epic affiliated tutorial series to help you get started:
Good luck creating your grinding system.
thanks for you reply
but I think its only for Splines?
i also want to grind on non spline objects (for example edges of mesh) or the objects i already have in my map
Hey @Botspence!
As far as I am aware, splines are the way you want to go as far as getting these working. You would add your splines to your existing objects (on the edges of the mesh) either in world or to them via blueprint if they are repeated or modular. Though, there may be other answers that others from the community may have or have come up with.
Okay Thankyou! 
Are there any easier methods for grinding which i can learn .
i want my character to grind everywhere where there is an edge like tony hawk games …