Hi,
you’ll have to place the .uasset somewhere within your “content” folder within you project for example: \Path\To\You\Project\Folder**\Content\Blueprints**
The folder structure you see in the content-browser is mostly the stuff below “Content”. A thing you’ll have to do as well for better user experience is to replace the meshes from the variables End Mesh/CrossMesh and Street Mesh/SplineMesh with your own meshes.
However, I’ll add a Blender scene with some example meshes so you can see how they should be build. Just give me a moment 