Tillig T1 02950 & 02951 - Unboxing, how to open and installing decoder 

The missing manual of the Tillig T1. In this video you see exactly how to open the model, how to get to the Next18 decoder slot and how to close it neatly without cables showing through the windows by removing the roof without damage.
In this video, a Train-O-Matic Next18 decoder is being installed.
Video on how to (practically invisible) install sound will follow soon.