Setting up a network via Chainlist.org using the Polygon network as an example

Go to the MetaMask wallet browser.

In the search box, enter the website address chainlist.org and click next.

In the window that opens, use the search function, or scroll down to the desired network and click "Connect Wallet”:

In MetaMask's pop-up window, confirm the wallet connection by tapping "Connect".

Without exiting the browser on the website page, click "Add To MetaMask":

In the Wallet window that opens, confirm the addition of the new network settings by tapping on "Approve".

Change the network if you plan to switch to this network immediately by tapping on "Switch Network":