If you already have a website published on your domain, note that editing the “www” record will replace your website with the landing page. To avoid this, please create a new CNAME record and configure it using the guide below.
Below are the first steps you will need to take inside your domain registrar before coming back to your Instapage account to finish the process by adding your new subdomain in the Domains Dashboard, as explained in this article: https://d.pr/GkVQ8Q.
In Squarespace, open your domains dashboard, then click the domain name to start editing its DNS records.
Click DNS, then DNS Settings
Scroll down to Custom Records and click Add record.
In the Type dropdown menu, select CNAME.
In the Host field, enter the name of the subdomain you are creating. For example, for https://lp.domain.com, enter "lp" without the quotation marks.
In the Data field, enter secure.pageserve.co (our server address), then click Save to complete the process.
You can choose any other name for your subdomain, including "www", as long as you do not have an existing record with the same name/host. It does not have to be "lp" as shown in our example.
You can head back to your Instapage dashboard and publish your pages to the new domain according to the instructions in the second part of this article here: https://d.pr/WfN7Pb.
You can find Squarespace's own guide about this here: https://d.pr/IP0rde