Does an example help? Because we have this small mod here, which only adds a religion. If not: Names and civilopedia entries are in the XML\GameInfo\ReligionInfo.xml, and these are again references to entries in the XML\Text folder. For the icons: There are 2 types. The easy one is the button, which is also referenced in the ReligionInfo.xml. You will need a grey button (for the case the religion is not yet founded), which has to be in the same place, and needs to have the same name, with a _d attached (e.g. shinto.dds and shinto_d.dds). The others are in the Assets\res\fonts\gamefont.tga. These symbols have to be in the same order like in the XML, first the religions, then the corporations. Don't edit that file by hand, do it with this tool. In case that's too fast, then post again (sorry, it's morning and I have to leave for work in a few minutes).