how to add arduino library in proteus 8 is shown in this tutorial. this is 100 % working and you can add arduino library in proteus 8.9 and proteus 8.10 by following the same instruction.
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For arduino library click the following link
https://drive.google.com/file/d/1yV5pCpzhq_Td8zuksWEae6Dqg-0E7l5v/view?usp=sharing

For Proteus 8.10 click the following link
https://www.youtube.com/watch?v=_ECZCpfQwZU

For Proteus 8.9 click the following link
https://www.youtube.com/watch?v=8WUGe-Go-38