How do I add a custom network to MetaMask on my Iphone?

Could you please walk me through the steps of adding a custom network to MetaMask on my iPhone? I'm a bit new to this and would appreciate a clear and concise explanation. Specifically, I'm looking for guidance on how to navigate the MetaMask app, where to find the settings for adding a custom network, and what information I need to input in order to successfully add the network. Thank you in advance for your help!