Add the following add A record to the domain:

DNS Record:
A coolify.example.com 8.8.8.8
A *.colify.example.com 8.8.8.8

Replace the domain and IP with actual values

Then

1. Login to Coolify
2. Click on Servers
3. Choose your server
4. Under configuration Wildcard Domain
5. Fill the domain https://coolify.example.com
6. Now add new project and click generate domain or enter your domain.
7. Deploy it will deploy with on that domain with SSL