Requirements
Prepare an attached domain, active TLS, a compatible PHP version, an empty document root and an available database. Choose a site name, administrator email and non-obvious administrator username before starting. Back up any existing destination content.
Install Joomla
Install Joomla on the intended domain and empty document root with the required language and administrator credentials. A dedicated database avoids collisions with other applications. Reuse an existing database only with its current password and a unique table prefix; never use one that is importing, restoring or already dedicated to another site.
Resolve an installation failure
Treat the first concrete error as the starting point. A non-empty document root must be inspected and either preserved elsewhere or replaced deliberately. An unknown database host normally means the supplied hostname is wrong or the new database is not ready; verify the exact remote hostname rather than substituting localhost. When Joomla asks for ownership verification during a manual installation, create or remove only the exact verification file it names and leave unrelated files untouched.
Complete initial configuration
Open the HTTPS site and /administrator, sign in and review System Information. Confirm the expected PHP and database versions, site URL, timezone, mail settings and the paths for logs and temporary files. Send a test email and save a harmless configuration change before adding extensions.
Recover administrator access
Use Joomla's supported account-recovery process when the administrator email is available. If database-level recovery is unavoidable, take a database dump first, identify the correct user and table prefix, and follow the procedure for the installed Joomla version. After access is restored, replace the temporary credential, review privileged users and confirm that configuration.php is not publicly readable.
Extensions, templates and cache
Install extensions only from maintained sources and confirm compatibility with the current Joomla and PHP versions. Remove unused extensions and templates rather than merely disabling them. After a template or extension change, clear Joomla's cache first and any hosting or CDN cache afterwards.
Updates and backups
Take matching file and database backups before updating Joomla core or an extension. Apply changes in a maintenance window, then test /administrator, the homepage, forms, menus and a representative content edit. Keep a portable database export and the current configuration.php file in the recovery set.
Diagnose common failures
A database connection failure requires checking host, database, username, password and prefix. HTTP 500 after an extension change requires the PHP error log and disabling or reverting that extension. Incorrect paths can break uploads, logs or updates even when the homepage works. Preserve partial installation resources until the first concrete error is understood.
Remove or recover Joomla
Restore matching files and database, confirm configuration.php connection values, clear cache and test both public and administrator routes. For removal, uninstall the application, inspect its root and verify database dependencies separately before deleting files or the database.
