thank you for your purchase.
That i can think of, there are 2 things you might consider:
1) is that the tiled map must be saved as base64 uncompressed (i forgot to say that in the video, but it does give you an error in Unity that should tell you this if you try to load another kind of map). The map must also be orthogonal (a grid map, not a hex map).
2) and the last few seconds of the intro video
- that your tiles in your 'setup scene' must be placed at tile size intervals
- that the position of your tiles in 3D matches their position in the texture map you are using in Tiled
- that variants are placed vertically as I show in the videos
- the tiles have to be placed along the x+ z+ quadrant with 0,0 at their upper left corner in Unity
in fact you don't even have to do the things in #2 in your 3D program if you would rather arrange your tiles manually in Unity. (I don't recommend this, but I tell you just so you know that doing the things in #2 in your modeling program is simply part of my suggested workflow, it is not a requirement for the tools to work). It's only important that they end up as described in Unity, and however you want to get your tile models into those positions in Unity is ultimately up to you.
I'm not totally sure if I answered your question though, can you be more specific as to where you are getting stuck?
Feel free to post more questions if you run into any trouble.