afv-library/samples/ui-bundle-template-app-react-sample-b2x/scripts/apex/hello.apex

// Use .apex files to store anonymous Apex.
// You can execute anonymous Apex in VS Code by selecting the
//     apex text and running the command:
//     SFDX: Execute Anonymous Apex with Currently Selected Text
// You can also execute the entire file by running the command:
//     SFDX: Execute Anonymous Apex with Editor Contents

string tempvar = 'Enter_your_name_here';
System.debug('Hello World!');
System.debug('My name is ' + tempvar);