Absolute world position in a blueprint

hey guys i am watching this tutorial [Paper2D: Project Setup | 02 | v4.4 Tutorial Series | Unreal Engine][1]

and it shows this screenshot at

the video explains some stuff but i still dnt understand, how 1) and 2) are multiplying to give the texture new visual.
If you can explain what absolute world position does too , is it (0.0.0) world coordinate?
repeats per meter parameter has 0 value stored, if we divide 0 with any number except 0, we get 0, wtf am i missing here…
and lastly a generic question, should i go learn c++ to have an understanding of a game engine from ground up, and if yes can you point me to a right direction book or smthg…? just a hobbysit that used for 10 years maya and MEL… i dnt rush doing stuff or smthg, got a job (nothing related to 3d and cgi) , i am just a 3d enthousiast that loves creating stuff