Need Help Migrating Existing Website to Squarespace

I'm new to Squarespace and am trying to help a friend with her existing website. She registered her domain with GoDaddy and it's hosted elsewhere. She's established an account on Squarespace and added me as a contributor. I designed her site and want to go live with it. Are there resources here to help with the steps I need to take? I looked around and couldn't really find what I was needing. 

I've been away from web design/development for a while so need a quick refresher. I believe I have to point the name servers in GoDaddy from the old hosting site (not GoDaddy) to Squarespace...? She's on the 2-week trial here on Squarespace--will she need to upgrade to at least the personal plan? I'm just not really sure what my next steps should be.

Any help would be most appreciated!

 - Bob

This looks perfect! Thank you so much for your quick reply.

Hopefully I'll be back with a report of "Success!"

Thanks again!

 - Bob

Success! Thank you Paul for your fast response. Everything went very smoothly.