take ShipComponentDefs.xml and strip all the components out paste in yours, make sure you leave the header alone and keep the closing tag so it looks like this.

<?xml version="1.0" encoding="utf-8" standalone="yes" ?>
<ShipComponentList
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="../Schema/ShipComponentDefs.xsd">
<!-- Created with the Gal Civ 3 Editor -->
<!-- ShipComponentDefs.xml -->

Paste your code in here

</ShipComponentList>

Then save that in your mod directory with a prepend to the name like RDS_ShipComponentdefs.xml

Do the same with ShipComponentText.xml just change one entry to match your <DisplayName>RepairDronesStrategic_Name</DisplayName> and <Description>RepairDronesStrategic_Dec</Description> and dump the rest and save it just like the previous file.

The files should go in “//MyDocuments/My Games/GalCiv3/Mods” create your own directory here and then add a Game and Text directory inside it.  The RDS_ShipComponentDefs.xml will go in the Game directory and the RDS_ShipComponentText.xml will go in the Text Directory.

Walla you have created your first mod and its append style so it shouldnt interfere with other mods or any patches.

If you leave the file named the same it must contain all the original contents though you can add your own stuff to it, this is an "overwrite" it will replace the original game file when the game starts up.  This is less desirable because it can interfere with patches and doesn't play nice with other mods.

If instead you strip out the contents and put in just your code, then name the file pretty much anything else as long as it ends in .xml the game will read it and add it in, this is be cause the game only really cares about the header and the footer tag.  This is known as an "append" it has the advantage that the game adds your code in without overwriting anything and you can generally have any number of append style mods running at once as long as all the internal names they use don't butt heads.