Add subdomains

[mbta98]

Hello, I would like to add the following sub domains to my account:

Account Name: mbta98

Add Sub Domains:
blog.gresikfootball.id

I will be moving these domains to ns1.heliohost.org and ns2.heliohost.org
Where/how can I modify the DNS's value for these domain?
E.g. for TXT records to enter SPF values?

Thank you and kind regards