The rightmost bit is the sixty fourth bit. The first step in the DES procedure is to change the order within each block. For example, the fifty eighth bit in the original string becomes the first bit in this new block. Bit fifty becomes bit two and so forth, as specified by a table. This step is called the initial permutation.
Permutation is used in the strict mathematical sense that only order is changed.
The results of this initial permutation are broken down into two halves. The first thirty two bits become L0. The last thirty two bits are called R0. DES algorithm seems to be feedback mechanism with the addition of a disturbance term. The key and the message become interwoven and inseparable.