How to prepare free 3D assets to importing?

I tried to search 3D assets. I load .blend file in Blender, export it with babylonjs plugin, but I can’t open it correctly in BabylonJS Editor. Usually it appears without textures and animations or completely invisible.

Typical example: HK416 with animation Free 3D Model - .blend - Free3D

Unfortunately, I completely new in 3D tools like Blender. So, most likely I just miss some important steps. Can anyone provide step-by-step instructions how to prepare external textured and animated 3D objects to import.

This topic could be worth a read Struggling with importing animations from Blender into BJS

A search of this forum for any of blender, blender textures, blender animations might also bear more fruit.

I would recommend to start with simple examples. Here are some good assets:

This folder contains several scenes, where each of them a glTF 2.0 feature is introduced.
Because of their simplicity, they are also a reference on how to implement a glTF 2.0 material in Blender.