Use tools on blueprints

I’m new to Unreal Engine, and would like to know how to use tools like “splines” on a blueprint (I used the Landmass plugin)
If this is not possible, how could I use it as a Landscape?
Thank you
(sorry I did not find a closer in category x’)

Thank you for your time, but that doesn’t answer my question, I probably misspoke:
I would like to plot a path on a mountain created from the LandMass (as said in the video), here is a screenshot of what I would like to do, but which is not working (the blueprint replaces the Splines):

thanks again =)