From the manual
http://www.z1simwheel.com/dashboard/manual/sims.cfm
The plugins are in your documents folder
documents/z1dashboard/plugins/<simname>
Rfactor2
The connection to rFactor 2 requires that you place the Z1SWRF2.dll or the Z1SWRF264.dll plugin into the appropriate rFactor 2 plugin folder. Both files are located in the documents/z1dashboard/plugins/rfactor2 folder. The Z1SWRF2.dll is for 32 bit versions of rFactor 2. The Z1SWRF264.dll is for 64 bit versions of rFactor 2.
Steam Installation:
The rFactor 2 32 bit plugin folder is located at \Program Files (x86)\Steam\steamapps\common\rFactor 2\Bin32\Plugins
The rFactor 2 64 bit plugin folder is located at \Program Files (x86)\Steam\steamapps\common\rFactor 2\Bin64\Plugins
Previous Installations:
The rFactor 2 32 bit plugin folder is located at \Program Files (x86)\rFactor2\Bin32\Plugins.
The rFactor 2 64 bit plugin folder is located at \Program Files (x86)\rFactor2\Bin64\Plugins.
You will need to copy the appropriate plugin into the plugins folder of your rFactor 2 installation. Once there simply start your Z1 Dashboard software and then start rFactor 2.
Note that there will be about a 10-20 second delay when you get in the car before rFactor 2 will start broadcasting data. This results in the software not detecting that you are in the car for those 10-20 seconds. You will notice a small 'plug' icon at the top left of your rFactor window which will shrink away when rFactor 2 starts to broadcast the data.