I’ve been using Houdini on and off for a couple of years. And some concepts are difficult to grasp. Especially if you coming from another 3d application.
There is short course that I can now recommend to anyone who want to start having fun with Houdini:
Houdini Made Easy 01 – The Core Essentials from Hipflask. It’s completely free.
They also have 50% off until April 30th, 2020 on 2 other courses. I finished them and can’t recommend enough. One of the best teachers and flow of presenting information.
Random short animation: