Applications
What an application is in OSS Panel, and the ways to create one.
An application is one site or service the panel runs for you: a domain, a system user that owns the files, a web-server configuration, and — depending on what you chose — a runtime, a database and an installed piece of software.
Everything else in the panel hangs off that: SSL is issued for an application's domains, backups run per application, and the firewall, logs and file browser are all scoped to one.
Where applications live
Applications in the sidebar lists everything on the server, with its type, PHP version, status, system user, size and age.

Until the first one exists the screen is a prompt to create it instead.
Three ways to get one
Install a ready-made app
WordPress, Nextcloud, Moodle and seven more — downloaded, configured and installed for you.
Deploy your own code
Clone a GitHub, GitLab or Bitbucket repository and build it on every deploy.
Start from nothing
An empty PHP site or a static directory you upload files into.
All three go through the same form. Create an application walks through it once, step by step; the pages above only cover what is different about their type.
Once it exists
Every application then has its own set of screens — domains and certificates, deploys, files, logs, backups, and the protection settings. Managing an application walks through each one.