The sample assets in the screenshots are in the example project at http://impreszions.com/splinemeshbuilder/RaveSplineMeshBuilderExample.zip (UE4.16)
Its in the SampleObjects.umap (stairs, chair, etc) and SampleScene.umap (the first screenshot). There were some items that I had to mess around the parameters under the Advanced category of the components to get them working so make sure to check the settings there too
Bonus tip!
The chair in the video is done by using 2 Mesh Bend functions. Take an extrude of a rectangle and bend it to a U-shape, then bend the U-shape into the S-shape.
Much like how you would do it in the real world =)
Another tip!
Straighten segment function in the spline drop down menu can potentially solve many mesh generation problems.
Thanks again for your support!