To transfer assets to BSC, you will have to use the Binance Bridge.
Step 1: Go to Binance Bridge.
Step 2: Connect your wallet.
Step 3: Select the asset you want to migrate (e.g. ETH or USDT).
Step 4: Select the network you want to transfer from (i.e. Ethereum) and network you want to transfer to (i.e. BSC)
Step 5: Select the amount of tokens you want to migrate and confirm the transaction. (You will have to pay a transaction fee.)
Step 6: Be sure to wait for the transaction to confirm.