Hello! We have some guides here for Namecheap registrar and Cloudflare, for those who need to manage external DNS: https://wiki.helionet.org/External_DNS_Hosting
I've never used IONOS, but the above guidance should give you an idea of what the IONOS dashboard would need you to enter, I think it should look similar enough across different providers.
If not, here's a plain-text explanation of what to do, in case it's easier to match up with whatever fields you see in your IONOS account:
To configure your DNS, you can either:
1) Set NS records pointed to the HelioHost nameservers: `ns1.heliohost.org` and `ns2.heliohost.org`, or
2) Manually create DNS records:
a) Add an A record (IPv4) pointing to your server's IPv4 address
b) Add an AAAA record (IPv6) pointing to your server's IPv6 address
To find the correct IPs, please go to: Login > Plesk > Websites & Domains > [domain name] > and check at the bottom of the page.
If after a full 2 hours your new domain doesn't work on your side, please make sure you clear your web browser cache: https://wiki.helionet.org/Clear_Your_Cache