How to bridge tokens from Ethereum to arbitrum?

Can you please explain the process of bridging tokens from the Ethereum blockchain to the Arbitrum network? I'm interested in understanding the steps involved, any potential risks or limitations, and if there are any specific protocols or tools that are commonly used for this purpose. Additionally, I'd like to know if the bridging process is reversible and if there are any costs associated with it. Thank you in advance for your detailed explanation.