Trouble Setting Up Staging Database

Hello I'm trying to set up a staging subdomain that I can use to push changes to a live site, but I'm a little confused. I'm currently trying to use step by step instructions to create this staging environment and I've noticed I now have two extra databases. One for the live site (user_database1) and then two for staging (user_staging and user_database2). I was wondering which one of these two domains I actually need for my staging subdomain to function on wordpress. Currently the subdomain is online and I can view it, but the instructions I'm following say I need to change the wp-config file to link my databases.