It basically let you control a lot of aspects of the game, settings-wise..
it is best to have all the modules installed and just go trough the settings afterwards, since the default settings are fine for the most part
the only modules I would go trough it's settings first would be the Pregnancy and the Population ones, as those have a bit different settings than the default ones to create a story progression in the world.
to change the settings after installing it you would need to click on an in-game computer > MCCC > settings
most of the settings are pretty clear and easy to manage, and if you get stuck you can read about the specific setting in the Documentation part on the website
you can also get help with setting it up over at MCCC discord channel
https://discord.gg/h6GkGyd