If you want to use this space to write your biography here, edit the index.md file. You can put a picture in, too. Rename your picture to profile.png and put it in the assets/images/ folder.
The social-icons footer can be used to link profiles from GitHub, OrcID and ReasearchGate aprart form the usual Twitter, LinkedIn and Facebook. You can add your user ID in the _config.yml file to link your accounts.