How do I???

[loopygram]

I'm not very computer literate so I need help please.
I have a D-Link 2001S ATA. I have purchased the SIP settings but that's as far as I got.
I likely sound really stupid here but where/how do I enter the information in the settings file?
I really need step by step instructions. I plugged the phone in and I have dial tone but when I call a number I always get the busy signal. Also calls to my number just to to voicemail. I can't hear it ringing.
There was a CD with my ata and I followed the instructions there for IP address etc and that's also scary for me so I may have screwed that up also.
Any and all help would be appreciated. Thank you so much