To get started with the Testnet, after installing Sui CLI, run sui client new-env --alias testnet --rpc https://fullnode.testnet.sui.io:443 to set up the environment, and then switch to it using sui client switch --env testnet. This setup will allow you to deploy contracts. For an alternative to a local setup, you can use public testnets like the Sui Testnet. Deploying on testnets helps avoid issues with your local setup since they are specifically provided for testing purposes.

If you have Sui CLI installed, you can deploy contracts to the Sui Testnet using it. You'll first need to set up a Testnet wallet through the Sui CLI by configuring it with a new environment pointing to Sui Testnet (https://fullnode.testnet.sui.io:443). Make sure to have at least 1 SUI gas coin, which can be obtained from the Sui Testnet faucet.