SPF records are TXT records placed into a domain's DNS settings.
SPF (Sender Policy Framework) is a way to restrict which mail servers are allowed to send email for your domain name.
SPF Record Configuration
Create a TXT record for the outgoing sending domain with the following details:
"v=spf1 include:spf.antispamcloud.com -all"
If you already have an existing SPF, simply add a:6205.submission.antispamcloud.com a:release.antispamcloud.com to your existing record.
Setting up DKIM
If your sending domains already sign with DKIM, then this should not be changed.
SpamExperts will simply forward the DKIM signed messages along to the recipient.
If there is no DKIM signing, you can decide to either sign this on your sending MTA, or sign with SpamExperts.
It's not obliged to sign with DKIM, however it often helps to "authenticate" as much as possible your senders.
Further information on how to setup DKIM with SpamExperts can be found here.
Setting up MTA
Instructions for configuring MTA records for different mail servers are located here.