Here's a zip file containing a simple UE project showcasing the many ways you can use the Procedural Mesh Component in Blueprints to build all sort of procedural meshes.
I documented the blueprints as best as I could to explain in details how to build your vertices and triangle indexes stack, amongst other things. There's 12 examples, starting from the simplest case, a simple quad. Then you're taught how to build a grid of quads, how to sample a displacement map, how to make a cylinder, a cone, how to use a spline deformation, then how to use vertex color and UVs to store additional data, then finally how to copy and manipulate data sampled from a static mesh.
I hope it's useful to any of you who aren’t familiar with the procedural mesh component yet!
Cheers