This is a step by step process showing you how to install Ubuntu Touch on your Nexus 5 device. To do so you can use the following link for the Multirom Manager: http://goo.gl/c6vKxY. MultiROM Manager can install or update MultiROM, it's recovery and kernels. It can also install Ubuntu Touch system-image based builds into MultiROM as a secondary ROM.
The Nexus 5 is a smartphone co-developed by Google and LG Electronics that runs the Android operating system. The Nexus 5 was unveiled on 31 October 2013. Ubuntu Touch for the Nexus 5 device is a Ubuntu community driven port. Community-driven ports to a much wider set of devices (including installation instructions) can be found here.