DirectAdmin is a lighter panel than cPanel or Plesk, and once you understand its one organising idea, the three levels, everything else is a short menu away. This is the map of the Evolution skin, the default skin on every current install, for someone opening it for the first time, whether that is as the server admin or as a user with a single site.
The three levels
Every login in DirectAdmin has one of three levels, and the level decides which menus exist.
Admin owns the server: services, IPs, updates, backups of everyone, and the resellers. Reseller owns a group of users: creates them, gives them packages and IPs, and sees their usage. User owns domains: files, mail, databases, DNS and SSL for the sites in that account.
The trick that confuses newcomers is that the levels nest. The admin account is also a reseller and also a user, so it can create accounts directly and can host a domain of its own. A reseller is also a user. This is why an admin who logs in and cannot find "Domain Setup" is simply at the wrong level; the page exists, one level down.
Switching levels and "Login as"
The level selector sits in the top bar. For an admin it offers Admin Level, Reseller Level and User Level; a reseller sees two; a user has none. Switching does not log you out, it changes which side of the account you are looking at.
To work inside somebody else's account, open Admin Level → Account Manager → Show All Users (or List Users at Reseller Level), find the account and use the Login as action. You are then in that user's panel with their menus, their files and their limits, which is how support is done: you see exactly what the customer sees. A link at the top returns you to your own account. Nothing about this is a security shortcut; the user's password is never shown to you.
The layout
The left sidebar groups everything. At User Level the groups are Account Manager, E-mail Manager, Advanced Features and Support & Help. Admin Level adds Server Manager and Extra Features. The dashboard shows usage against the account's limits, and the search box at the top finds any page by name, which is faster than the sidebar once you know what a page is called.
The ten things new users do first
1. Upload a site
Account Manager → File Manager. Each domain's document root is /home/<user>/domains/<domain>/public_html. For more than a handful of files use FTP or SFTP with an account from FTP Management.
2. Install WordPress
Advanced Features → WordPress Manager, or WordPress in the sidebar. It installs, updates, resets passwords and clones sites. Details in installing WordPress with WordPress Manager.
3. Get an SSL certificate
Account Manager → SSL Certificates, choose the free Let's Encrypt option, tick the names you want covered and save. Then turn on the HTTPS redirect in Domain Setup. Walkthrough: free Let's Encrypt SSL in DirectAdmin.
4. Create an email address
E-mail Manager → E-mail Accounts → Create Account. Set the address, password and quota; the page afterwards shows the IMAP and SMTP settings for a phone or Outlook. Webmail in the same group opens Roundcube.
5. Add a domain, subdomain or pointer
Account Manager → Domain Setup for another full domain, Subdomain Management for blog.example.com, Domain Pointers for a second name that should show the same site. Each is explained in adding a domain, subdomain and pointer.
6. Change the PHP version
Account Manager → Domain Setup, click the domain, and pick the PHP version from the list the admin has made available. On a CloudLinux server there is also Advanced Features → Select PHP Version with per-account extensions.
7. Edit DNS
Account Manager → DNS Management. Add or change A, CNAME, MX and TXT records for the domain; changes are live within a minute if this server runs the nameservers. If the domain's DNS is at Cloudflare or the registrar, this page has no effect and you edit records there instead.
8. Create a database
Account Manager → MySQL Management → Create new Database. Databases are named username_dbname. phpMyAdmin is linked from the same page and logs you straight in.
9. Take a backup
Account Manager → Backup/Restore. Choose what to include, create the backup, download the archive from the list. The admin also runs server-wide backups of every account; yours is for the copy you keep yourself.
10. Schedule a task
Advanced Features → Cron Jobs. Give it a schedule and a command; the command runs as your user, so use the full path to the PHP binary for that version.
Things worth knowing
Site Summary / Statistics / Logs under Advanced Features shows disk, bandwidth and the Apache error log for each domain. A 500 error or a blank page is explained there before anywhere else.
Two-Step Authentication is under Account Manager. Turn it on; the panel has access to everything.
Support & Help has a ticket system if the admin enabled it, and a link to the DirectAdmin documentation for the current page.
Little changes between DirectAdmin versions, so once you know these pages you can manage any DirectAdmin server. If you are the admin, the next thing to learn is the account side: creating packages and user accounts.