[ERROR] Failed to perform transaction

I am following libra documentation on My First Transaction, everything worked fine until Submit a Transaction. As mentioned in the following document, I tried to submit a transaction. https://developers.libra.org/docs/my-first-transaction#submit-a-transaction

But it fails with below error, tried going thru troubleshooting articles, but not much helpful.

libra% transfer 0 1 10
>> Transferring
[ERROR] Failed to perform transaction: Transaction failed with vm status: Validation(UnknownScript)

I tried switching to testnet: git checkout testnet
and receive this error:
fatal: not a git repository (or any of the parent directories): .git
So, I appreciate any explanation and help for the trouble above.

Please check this post. Transaction failed

Use this testnet repository

i think this issue is going to be repeated several times :roll_eyes::grimacing: