How do I add Injective to MetaMask?

Could you possibly enlighten me on the steps involved in incorporating Injective into my MetaMask wallet? I'm a bit perplexed about the entire process and I'm eager to understand the specifics. Do I need to install any additional extensions or plugins? Is there a specific network or chain I need to be connected to? Also, would you mind clarifying whether there are any fees involved in the process? It would be greatly appreciated if you could provide a step-by-step guide to adding Injective to MetaMask, ensuring I don't miss any crucial details. Thank you in advance for your assistance.