revamping a website

HELP! I am trying to redesign a current website for my 501 (c) 3 non-profit organization. We have recently renewed the  domain on Squarespace, and I have started a new trial website which expires in 2 days. I need to know the best way to "transfer" the current domain to the new site I have created. The original designers are no longer on the project, and all I have is the old email and password log in. I was not given any other ability to change the original website. HELP! Is there anyone I could actually talk to, to work through this problem? I'm "old school" (retired teacher) and I could use a listening ear.  Thank you!

Hi, 

Email me at gabe@gdcarter.com and I will share my phone number. 

I'd love to help if possible. I just connected a domain to a  new site for a client. I hope I can be of some assistance. 

I don't have any $$ for you; can you still help me? 

I'll try my best, do you know if the old domain is managed by Squarespace or a third party? 

The old domain is on Squarespace. Is it possible to transfer that domain to the new site I have made (trial basis), then cancel the old site, and then activate the new site with the old domain?

Yes, you can transfer a domain you own between sites.  Visit the site of the domain you wish to transfer. Click on the Settings options in the dashboard. Navigate to domains and select.  Near the bottom, there should be an option that says "Move domain to another site" once you press that you should be able to select the new website you wish to move it to. 

I've attached a screenshot of what it looks like on my site. 

Thank you - I am on with the live chat on Facebook Messenger - I cannot do this until I activate the trial website, but as soon as I have our credit card #, I should be good.  Thank you!!

Awesome! You're welcome, I hope it's a breeze for you after you get situated.