Open a terminal and do the following
sudo apt-get install -y devscripts build-essential equivs
git clone git://git.linuxcnc.org/git/linuxcnc.git lcnc
cd lcnc
git checkout -b origin/joints_axes13
cd debian
debian/configure uspace ; debuild -uc -us

Open the file manager and double click on the following files and install them
with Gdebi
linuxcnc-uspace_2.8.0~pre1_i386.deb
linuxcnc-doc-en_2.8.0~pre1_all.deb

Menu > Preferences > Main Menu
CNC uncheck each item then recheck or they don't show up in the menu.
New Item
Name: Latency Histogram
Command: latency-histogram
click on icon and go to /usr/share/pixmaps and pick linuxcncicon.png
click ok and close and you should be up and running with LinuxCNC Joints Axes 13