Box Creation issue : invalid Box reference " MyKey"

Hey guys, I’m a computer engineering student, I’m trying to create a smart contract and I need a bit more space to store my data, so I choose to use Boxe storage. But when I create the box using the “box_put” opcode I found this error:

How can i fix it ?

Did you provide the right box reference in the transaction?
Boxes used by a smart contract need to be referenced in the transaction calling the smart contract.

See boxes= in Contract storage - Algorand Developer Portal

thank’s i saw now the link
i’ll try !!!