You can manually configure your wallet, by adding Moonbeam network with the following settings:
Network Name: Moonbeam
Network RPC URL: https://rpc.api.moonbeam.network
Chain ID: 1284
Currency Symbol: GLMR
Block Explorer URL: https://blockscout.moonbeam.network/
After you've opened the Network tab, scroll down and click "Custom RPC"
Fill in the details with the Moonbeam settings (at the top of this page).