WMS 3.0 Help

I'm trying to install  WMS 3.0 however I'm doing a custom install as we'd like to have our databases on a separate server than the application server. However when I select the custom install, it's asking me to connect to the remote database for Mongo/Maria. This is where I'm a bit loss as I'm not a DBA and this is my first time setting up WMS 3.0 as our previous administrator left. Where can I get a guide on how to setup Mongo/Maria and the databases to remotely talk to WMS?