the default instructions assume you have root and are intended to provide the most convenient use by placing the phar package in your path
alternative 1:
remove the sudo, change /usr/local/bin/wp to /path/to/your/installation/wp, and instead of calling the commands with wp command <parameters> use ./wp command <parameters>
alternative 2:
remove the sude, change /usr/local/bin/wp to /any/other/path/wp and instead of calling commands with wp command <parameters> use /any/other/path/wp command <parameters>