Adding custom tokens to Metamask is a simple process. First, click on the "Add Token" button in the Metamask wallet. Then, enter the token's information such as contract address, symbol, and decimal places. This information can be obtained from the token's official website or a trusted source. If the token is not listed in the predefined list, you can manually enter the information. Once the information is entered, click "Add" and the token will appear in your Metamask wallet. You can repeat this process for multiple custom tokens and keep them in one convenient place for easy access. It's important to double-check the information before adding the token to ensure the security of your funds.