I have been following tutorial by unreal ‘Shaders in UE4’ and couldn’t find a node called transformVector.
Right click on the mouse, searched transformVector, but couldnt find such node. Am I doing something wrong? plus, I couldnt find ‘Absolute World Position’ node either… since I am a newbie, I cannot solve this small problem 
Please see the EDIT at the end, instead of doing this long route. I leave the long route in, so people can further understand what exactly is happening with nodes.
This one ticked me off too. Absolute World Position red node comes from a built in engine c++ class. in your content browser, view options, enable Show Engine Content. The actual name of what you are looking for. for Absolute World Position is MaterialExpressionWorldPosition. Search for ‘position’ in Engine C++ Classes and you will see it. Drag it into your blueprint. you now have the Red World Position Offset you are looking for.
The fact that it does not come up through searches in the pop up dialogs within blueprints baffles me. perhaps i just do not know what to call it. IDK, but that is what you are looking for.
Good luck.
Edit, in the right click search menu from within your blueprint, it is under ‘coordinates’. it is called WorldPosition.
Still looking into the other part of your question.