Nothing here has to be done before you launch — but this order avoids rework.
1. Branding first (Design → Change Site Design). Colour scheme, logo and favicon. Do this before anyone sees the network; first impressions of a template are hard to undo.
2. Storage next. Point the network at your provider — Amazon S3, DigitalOcean Spaces, Backblaze, Google Cloud Storage, Wasabi (via S3 or FTP) or a standard FTP server. Do this before members start uploading, not after.
3. SMTP third. Nothing else works properly if the network cannot send email: invitations, notifications, confirmations. Set it up under Settings → E-mail & SMS Setup.
4. Media handling. If members will upload video in anything other than MP4, enable FFMPEG under File Upload Configuration → FFMPEG System Settings and run the built-in debug check.
5. Payments and monetization — only when you need them. There is no benefit to configuring a gateway before you have something to sell.
6. Video, audio and SMS last. Optional, billed by the provider, and easiest to add once you know whether your community actually wants them.
Rule of thumb: configure anything that touches stored data or delivered email early; configure anything billed per use late.