Tiny OS

Hi everyone!
I hava a PIC18F2520 Interface Board with X-Bee wireless option:
<a href="https://microcontrollershop.com/product_info.php?products_id=2370" target="_blank" rel="nofollow noopener noreferrer">PIC18F2520 Interface Board with XBee Wireless Opti</a>
I want to write tiny OS and upload it to the board above. Is it possible? If yes, how must I do?

Thanks !