migrating wp

I have never migrated a website before so I am in need of assistance. A third party created, managed and hosted our WordPress website. We now want to control it ourselves and host it on GoDaddy. I have received the backup files and the CMS and Database Information from this third party. Now I want to migrate my current site on word press over to GoDaddy without losing anything and keeping the same domain name. Can anyone provide instructions on how I would do this or a good source for getting the information? Is there anything I need to do on the WP side first before migrating?

Thank you in advance.