Go to Settings in your wallet and locate Networks. You might have to manually add a network and input the following details for Base Chain:
Network Name: Base
RPC Endpoint: https://mainnet.base.org/
Chain ID: 8453
Currency Symbol: ETH
Block Explorer: https://basescan.org
Click on CONNECT TO BASE after saving. Upon completing this step, you should be able to connect to Base by choosing it from the network selection menu in your wallet.