If you need a detailed explanation i guess you are better off searching some tutorial site; there might be quite a lot of ground to cover depending on your current level of understanding the nitty-gritty details of a computer ☺
There may also be lessons on bitshift operators on here, I haven't checked yet.
The gist would be that "n << m" shifts the bits of n collectively m positions to the left filling up on the right with zeros.
Right shift works similarly but you have to distinguish between a pure binary shift and arithmetic right shift.
The use is often a quick way to multiply (left shift) or divide by (right shift) powers of two; in fact: n << m is n * 2^m. Multiplication and especially division are expensive operations. Shifting bits is fast in comparison. These operators appear where a lot of those kinds of multiplications and divisions occur in order to speed up the computation.
More use case may apply ☺
Maybe I find a lesson link on here ...
Here is one: