Two WP logins for site

Hi there (Im not very WP-savvy but I'm learning so please bear with me!)

I recently got my new site live using a helpful lady on Fiverr - she re-pointed my DNS from my old site to my new site, but I'm a little confused because she made a copy and sent new logins.
At the time I didn't understand why so I carried on using the old WP site ( )however I've now realised should I be using the new one she created?
I have sent an attachment showing what she did.
Im not sure what the difference is so wanted to check with your experts first. I can see my WPMUDEV dashboard and the updates I have made is on the old site and not the new one, but before I add to the new site I wanted to ask you (incase I mess anything up). Thank you!