Identifying External Coin (Fungible token) in smart contract

Hi, I’m very new to Sui.
How can I identify a certain coin in my Move smart contract? For example in Solana, I can accomplish it by just using constant 32 bytes public key but it seems much more difficult in Sui.
Please illustrate with LBTC as example.
I can find LBTC in Suiscan mainnet is identified as 0x3e8e9423d80e1774a7ca128fccd8bf5f1f7753be658c5e645929037f7c819040::lbtc::LBTC and also find git repo in https://github.com/lombard-finance/sui-move-contracts.