Hey @bentsajulia
If you’re planning to host this at the root domain, not as a sub-domain then you should…
FIRST: Delete the “A” record (the first one on your screenshot) since this is why you’re seeing the “already has a record” error.
THEN: Create the CNAME as follows:
Name: sblbapp.com
Target: hosting.adalo.com
(Looks like there’s an extra dot after the .com in your screenshot, you don’t need that!)