https://testnet.flowscan.org/

there are two account in transfer step, NFT owner and receiver

1. OWNER deploy contract on flow chain ,and create collection to owner's account (output : AccountContractAdded -> 0x2f55...(example))
2. OWNER mint and deposit NFT to owner's collection
3. RECEIVER create collection for his account
4. OWNER transfer NFT to receiver

1. test on emulator (O) -> put meatadata in NFT (O) -> random mint NFT (O) -> renew metadata(bonus)(O) -> constraint: no bonus, no transfer(O) -> change name ->account to owner / receiver(O) -> in makefile, _nft -> NFT (O)

2. test on testnet (use explorer on testnet) -> check cmd for whale steps

• start emulater

flow project start-emulator --config-path=flow.json --verbose

• deploy contract

// command
flow accounts add-contract $CONTRACT_NAME $CONTRACT_PATH
// example
flow accounts add-contract ExampleNFT ./cadence/contracts/ExampleNFT.cdc 

• send transactions

// command
flow transactions send $TRANSACTION_PATH --signer $SIGNER
// example
flow transactions send ./transactions/MintNFT.cdc --signer emulator-account

• send script

// command
flow scripts execute $TRANSACTION_PATH
// example
flow scripts execute ./transactions/MintNFT.cdc

• create account

flow accounts create --key --signer

• create key

flow keys generate

• random function : https://docs.onflow.org/cadence/language/built-in-functions/#unsaferandom