Steps for converting a TinkerCad 3D file to .babylon format using Blender:

Step 1. Download the BabylonJS zip file from the BabylonJS GitHub

Step 2. From the Export/Blender folder, import io_export_babylon.py into Blender. Details

Step 3. Make a copy of the current page and place the iss.babylon file in the same folder.

Step 4. Import .stl file from TinkerCad.

Step 5. Export your own .babylon file from Blender and add a line like this:

var iss = loader.addMeshTask("iss", "", "./", "yourfile.babylon");

Start here to learn more
BabylonJS Tutorials
Tutorial by Oimo Creator