I’m trying to make a slide mechanic so you can slide down a slope but I don’t know how to detect the slope and move a player down the slope based on how steep/long the slope is. Any help is appreciated 
This may be of interest to you. (I checked it out from another thread.) Not a solution or an explanation, but it contains a dive and slide mechanic which you may be able to adapt for your use case. I believe the idea is to use a physical ball which rolls down the slope and dictates the alignment of the character. Though if I were to approach this problem, I might start by attempting to simulate the physics of sliding down the ramp using a VectorForce and other constraints alone. I am not too certain how feasible that would be, however.
A simple way to achieve this would be using raycasting to get the normal of the slope, after that you just move the character according to the normal and its root position.
I also recommend using AlightPosition for this mechanic.
What would something like this look like I’ve been searching a real solution for the slope but I haven’t found anyone with like an exact tutorial