You can create A records that simply point to your droplet’s IP address. There is no requirement to use the DigitalOcean DNS services. In general to point a domain you plan to use for a website you would create the following two A records.

@   A  [droplet IP address]  

This record will point your domain when no subdomain is used (ie. http://example.org). In some systems you would leave the address field blank instead of using a @ symbol. If @ is not accepted try submitting it as blank or entering your whole domain with a trailing dot “.” after it like this example.org.

Then create the following for the www subdomain so www.example.org goes to your droplet as well.

www   A   [droplet IP address]