Setup Polygon Network
Head over to https://maticmike.club/guide/#setup and wait for the prompt to pop up with your MetaMask wallet. Confirm and you're done.
If no prompt popped up, simply follow the guide indicated in the website.
Go to https://polygonscan.com/, scroll to the very bottom and click on "Add Polygon Network", click confirm, allow switch network, and you're done.
Polygon Network = Polygon Mainnet = Matic Network = Matic Mainnet.
People get confused on the name but they are often just one and the same.