Unfortunately there is no aggregated place for all of the config you can perform, that is something we should look into. For now I would recommend starting with this wiki page to get the basics: http://wiki.alfresco.com/wiki/Alfresco_Share
After reading that please take a look at the share-config-custom.xml.sample that you have in your installation at share/WEB-INF/classes/alfresco/web-extension/share-config-custom.xml.sample
As you probably now already you can activate your custom configs by renaming that file to share-config-custom.xml (and preferably place it outside the share.war artifact, i.e. in TOMCAT_HOME/shared/classes/alfresco/web-extension/share-config-custom.xm) and then restart your server.
In share-config-custom.xml you can override all configurations that has been made in all the other share-xxx.xml config files.
I.e. share-config.xml share-datalist-config.xml share-documentlibrary-config.xml share-form-config.xml share-workflow-form-config.xml
So for now I would recommend looking into those files (most of them contain comments where needed that describes what they do) to get the full picture of what is achievable to configure.
Is there a specific config you're looking for or are you only looking around at what's possible?
