I wasn't an arduino person til lately, either.
Arduino IDE is yet another development-environment (think AndroidStudio, Xcode, Visual Studio, ...), aimed at various incarnations of arduino hardware.
Your prusa uses a rambo incarnation of arduino hardware - rambo is made for use with 3d-printers.
The rambo hardware runs marlin-based firmware.
Grab arduino version 1.6(.0) from ~ http://arduino.cc
Grab prusa-sources on github https://github.com/prusa3d/Prusa-i3-Plus
If you've got arduino 1.6 & the github repository locally, copy the ArduinoAddons/Arduino_1.6.x/hardware/marlin directory into your install-directory for arduino 1.6/hardware directory.
Once you copy that marlin directory, you may need to restart arduino ide, & now under Tools->Boards, you should select RAMBo.
You also may need to rename the arduino IDE install-path Arduino/libraries/LiquidCrystal/src to ...LiquidCrystal/src-tmp (as of this writing, to avoid a compile-time name collision with the current prusa github repository).
You will find a Prusa-i3-plus-master/Firmware/build.sh script.
This script builds the entire universe of prusa firmwares.
If you choose to use this, you will wish to modify build.sh's various hardcoded paths to reflect your environment.
If you wish to use the arduino IDE to build for only your single prusa version-target, you may copy your chosen version from Firmware/variants/ (ex.: 175-RAMBo1-3a-en.h) into Firmware/Configuration_prusa.h
There are (currently) 4 rambo hardware versions - refer to the diagrams at the bottom in the Firmware section as http://www.prusa3d.com/drivers/ to determine your version.
arduino IDE File->Upload sends your built firmware to the rambo. Upon upload, the screen on my prusa looked crazy (overwrote the character sets memory or so?). I waited a few minutes, then cold-rebooted the machine, & was up to version 2.2.3b.
You may also find some useful information in the comments about win 10 source-build that I wrote, at the bottom, over here:
Update RAMBo mini firmware (OLD method)
Hope this is helpful/time-saving, I just figured this all out lately too...