Hi,
YawPerSecond was a float variable that I made to store the number of degrees that I wanted the object to turn per second. Say, like 60. That ‘X’ node just multiplies two values. So, it’s multiplying the delta time (the time in seconds since the last tick) by the number of degrees that I want it to turn in a second. If the game is running at a steady 30fps, it will set the Yaw in that Make Rot to 2 degrees (.0333 seconds * 60 degrees/second); causing the object to rotate 2 degrees each frame.
Hope that clears things up!