I'm totally new at server things.

I have an ip address from digitalocean. x.x.x.x
I have a domain from namecheap. www.mywebsite.today

I tried this:
In Namecheap -> Manage Domains -> Modify Domain tab.
Host name -> @ -> x.x.x.x -> Record Type (A)
Host name -> www -> www.mywebsite.today -> Record Type (URL FRAME)

I got 400 Bad Request message.

And in DigitalOcean -> DNS tab i deleted all NSX.DIGITALOCEAN.COM. things.

How can i synchronize these?