Bit shifting is nothing but what it literally means: shifting all bits in a given sequence left or right.
All you have to remember is that every decimal number (like 6, 7, 3, 2) is represented as a sequence of bits in the memory of the computer. So if you find something like this in a piece of C code:
(7 >> 1)
it means that the bits in the underlying binary representation of 7 are to be shifted right by 1 position.
I think the explanation in the link you cite is pretty clear. Maybe writing down a sequence of bits on a paper yourself and manipulating them as in the cited link can help.
Or perhaps you don't possibly yet have the understanding how computers work with numbers internally. In that case, before learning bit shifting, you need to read about that.
