Step 1 - On Metamask go to Settings > Networks > Add Network
Step 2 - Set Network Name: Celo (Mainnet)
Step 4 - Set Chain ID: 42440
Step 5 (Optional) - Set Currency Symbol: CELO
Step 7 - Switch network to "Celo".
Step 4 - Set Chain ID: 42220
Step 5 (Optional) - Set Currency Symbol: CELO
Step 7 - Switch network to "Celo".