Switch to Polygon

Click on the 'Main Ethereum Network' button to expand a small window.

Click on 'Add Network'.

From "Polygon Mainnet" from the list, click on "Add".

A popup will appear with some information about the network, asking for confirmation. Click 'Approve'.

Now that the network has been added, the wallet will ask if you want to activate it. Click 'Switch to Polygon Mainnet'.

A new popup will confirm the network switch. Click "Got it".

Your wallet will now display a different currency, MATIC, and will be able to manage your tokens on Polygon.