I accidentally erased my macbook from find my iphone and don’t know how to restore it

With Modifications to previous instructions.

Computer off >>Plug into Charger. Startup computer and immediately hold the Command + r - key. Be very watchful for the Wifi Icon. You will be required to manually Enter the Wifi Password. Once a connection is established , presented with Options and choose Install or Reinstall macOS. This will connect to the Apple Servers and download the macOS what was previously installed. This if the Full Installer so depending on your Speed and Apple Servers cold take some time. Once it is done - the installer will automatic start and just follow prompts. There might be several Automatic Restarts - Normal. The on the final Reboot - Setup Assist will be presented . Like a Brand New Computer first startup.

Computer off >>Plug into Charger. Have the Time Machine Backup available but not yet connected. Startup computer and immediately hold the Command + r - key. This will start in Recovery Mode and presented with Options. Attach Time Machine Backup to computer and choose Restore from Time Machine.