The NS records decide who hosts your domain name, not your website. These should not be changed. If Etisalat host your domain name, these should point to the Etisalat nameservers.
If you aren't sure how to change the DNS records then I recommend that you contact Etisalat for support.
First, create an unlinked page named "Terms and Conditions"
Next, add a checkbox field to your form that only has one option "I Agree" and make it a required field. Put the following code in the field name:
I have read, understand, and agree to the website <a href="https://www.yoursite.com/terms-and-conditions" target="_blank">Terms and Conditions</a>.
I've included a screenshot of how I did something similar on one of my clients' sites.