The setup screen shows the records to add with their exact values; you never work a value out yourself. Depending on your DNS provider you get one of two paths.
Two NS records: You delegate your sending subdomain (for example send.yourcompany.com) to Outfound, and Outfound writes all the records below in that subdomain itself; your main domain's records are not touched. Add the NS records in the DNS records screen; don't change your domain's nameservers, or your website and email stop working.
Eight records: You add the records yourself. What they do:
- SPF and DKIM: prove that the email really comes from you, through an authorised server. DKIM is two records.
- DMARC: tells receiving servers what to do with mail that fails the SPF/DKIM checks.
- Sending CNAME: connects your sending subdomain to Outfound's sending infrastructure.
- MX: lets your recipients' replies reach Outfound; reply tracking depends on it.
- Link branding: makes the links in your emails show your own domain.
SPF, DKIM, DMARC and the sending CNAME are required for sending. A missing link-branding record doesn't block sending, but a wrong one does. A record marked Replaces the current record takes the place of your existing record with the same name; don't add it as a second record (two SPF records, for example, break sending).
You don't need to add a reverse DNS record; Outfound writes it on its own domain for you.