Order is important to not break any mail route or cookies:
1. Company name + portal name in Settings → Identity
2. Dark logo + light logo + favicon uploaded
3. Primary color + accent color configured — takes effect directly on /changelog too
4. Custom domain (Settings → Domain) — enter subdomain, place CNAME record at your DNS, wait for green "Verified"
5. Connect own mail account in Email → Accounts (Gmail/Outlook/IMAP)
6. Sender email configured under Settings → Email — set the just-connected account as default sending account
7. Test booking page + welcome email on new client account
Wait 2-3 min after each step for the cache. This way your portal is fully brand-compliant before the first client sees it.