All the Hysteria Tutorial maps that you can also found on the server named so.
I encourage you to play online if you can as you'll often meet players ready to help you learn Obstacle.
First, i advise you to play the "Hysteria Tutorials" maps in order, 1 to 3. Then you can continue on the training ones if you want, then exercice ones or any map you'd like. Progressive maps like Step by Step or Are you skilled?, learning others techs like RWJ (Rocket Wall Jump), etc.
A
GDoc is available here to help you know where to go to learn SM Obstacle, by listing good maps to do so.
Alternatively, and as this GDoc is still in the making for the time being,
you can check this mappack to go further and learn the various techniques available.