touch gulpfile.js (Then run this command)

var gulp = require(‘gulp’);
gulp.task(‘default’, function() {
//Here is the code for the default task
});

——–Even after trying all the steps getting below error————-

F:SPFxapp-extensions>gulp trust-dev-cert
[20:42:26] Using gulpfile F:SPFxapp-extensionsgulpfile.js
[20:42:26] Task never defined: trust-dev-cert
[20:42:26] To list available tasks, try running: gulp –tasks

F:SPFxapp-extensions>gulp serve
[20:42:59] Using gulpfile F:SPFxapp-extensionsgulpfile.js
[20:42:59] Task never defined: serve
[20:42:59] To list available tasks, try running: gulp –tasks

F:SPFxapp-extensions>npm install –save-dev gulp
npm WARN saveError ENOENT: no such file or directory, open ‘F:SPFxapp-extensionspackage.json’
npm WARN enoent ENOENT: no such file or directory, open ‘F:SPFxapp-extensionspackage.json’
npm WARN app-extensions No description
npm WARN app-extensions No repository field.
npm WARN app-extensions No README data
npm WARN app-extensions No license field.
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.13 (node_modulesfsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.2.13: wanted {“os”:”darwin”,”arch”:”any”} (current: {“os”:”win32″,”arch”:”x64″})

+ gulp@4.0.2
updated 1 package and audited 503 packages in 4.078s