How to place the ~/.composer/vendor/bin directory in your PATH?

I'm on Ubuntu 14.04 and I've been trying all possible methods to install Laravel to no avail. Error messages everything I try. I'm now trying the first method in the quickstart documentation, that is, via Laravel Installer, but it says to "Make sure to place the `~/.composer/vendor/bin` directory in your `PATH` so the Laravel executable is found when you run the Laravel command in your terminal." so my question is, how do I do that? This may be a simple question but I'm really frustrated and would appreciate any help.