Open the Source code repo and identify the latest PCB version. Take the Gerber files and send them to a PCB manufacturer or make them yourself: toner transfer works great and the boards were designed to be easy to make.

Check the BOM list and the schematics, and get all components. There are only a few, so this will be easy. Start soldering everything. This brings a lot of fun, as the entire design is done with through hole components, so easy to do with basic tools like just a soldering iron.

With the device assembled, download the source code from Github.

Go to the uRADMonitor Dashboard and create a user account. Visit the API tab to retrieve the user ID and the user KEY that you need to add to the code. 

Compile the code, and use an usbAsp programmer (or any other that works) and burn the fuses and the software into the microcontroller. 

The KIT1 shows all readings on screen. Additionally, the firmware creates a local webserver, so if connected to your network via Ethernet, you'll be able to open the unit's IP in your browser to access the internal page for data access. Finally, via the Dashboard, you can use the uRADMonitor cloud API to access readings.

To summarise, for the Data access, there are 3 possibilities:

1. Programatically, via the uRADMonitor Cloud API . Please see details on www.uradmonitor.com/dashboard or in this quick example: https://www.uradmonitor.com/wordpress/wp-content/uploads/2017/01/uradmonitor_api_example_response.pdf
2. Via the dashboard, in CSV or JSON format, see the DATA tab on www.uradmonitor.com/dashboard
3. The uRADMonitor units with Ethernet or Wifi connectivity (including the A3) come with an embedded micro web server, that can be used to access the readings directly in your LAN, by connecting to the unit. Here's what others did with this feature:
http://www.uradmonitor.com/weather-vs-radiation-readings/
http://www.uradmonitor.com/howto-upgrade-uradmonitor-graph-local-statistics/
http://www.uradmonitor.com/topic/new-firmware-enables-rrdtool-graphing/
http://www.uradmonitor.com/topic/include-uradmonitor-in-monitoring-software/
http://www.uradmonitor.com/topic/setup-local-graphs-for-your-uradmonitor/
http://www.uradmonitor.com/topic/uradmonitorx/
https://www.uradmonitor.com/firmware-upgrade-a3-wifi/