Step 3: Copy and paste these files in LIBRARY folder of Proteus In our example it is ARDUINO.IDX and ARDUINO.LIB You will see two files names as *.IDX and *.LIB in some cases third file is *.HEX. If you are using Proteus 8 Professional, then the library folder link will be something like this: “ C:\Program Files\Labcenter Electronics\Proteus 8 Professional\Data\LIBRARY” If you are using Proteus 7 Professional, then the library folder link will be something like this: “ C:\Program Files (x86)\Labcenter Electronics\Proteus 7 Professional\LIBRARY“

Step 4: Close Proteus Software and reopen it to check it.

You can find that adding library to Proteus, Arduino, Eagle is same just copy and paste the library files at proper location.