In \Data\Mods folder your mod should has following structure:

yourmodname
|
+- Data
       yourmodname.pak
|
+- Localization
        english_xml.pak
        german_xml.pak (optional/additional other languages)
changelog.txt
mod.manifest
readme.txt


Content of yourmodname.pak:
Libs
    |
    +- Localization
             localization.xml


In localization.xml:
<localization>
    <init>
<entry>text_ui_HUD.xml</entry>      <-- vanilla entry unchanged + must be stay here
<entry>text_ui_ingame.xml</entry> <-- vanilla entry unchanged + must be stay here
<entry>text_ui_items.xml</entry>    <-- vanilla entry unchanged + must be stay here
<entry>text_ui_menus.xml</entry>  <-- vanilla entry unchanged + must be stay here
<entry>text_ui_misc.xml</entry>      <-- vanilla entry unchanged + must be stay here
<entry>text_ui_soul.xml</entry>       <-- vanilla entry unchanged + must be stay here
<entry>text_ui_tutorials.xml</entry><-- vanilla entry unchanged + must be stay here
<entry>text_ui_minigames.xml</entry>   <-- vanilla entry unchanged + must be stay here
<entry>text_rich_presence.xml</entry>   <-- vanilla entry unchanged + must be stay here
<entry>text_ui_ingame_yourmodname.xml</entry>   <-- This entry would be added in Mod CLAM
<entry>text_ui_HUD_yourmodname.xml</entry><-- OR/AND this entry would be added in Mod CLAM
</init>
.... snipp


In english_xml.pak (And for others languages):
text_ui_ingame_yourmodname.xml            <-- Only this entry must be here
text_ui_HUD_yourmodname.xml                 <-- Or/and this entry must be here


In text_ui_ingame_yourmodname.xml (UTF8 without BOM - Example only for german_xml.pak):
<Table>
<Row><Cell>ui_open_nest_searched</Cell>    <Cell>Examine nest</Cell><Cell>Nest untersuchen (durchsucht)</Cell></Row>
<Row><Cell>ui_open_stash_searched</Cell><Cell>Open</Cell><Cell>Öffnen (durchsucht)</Cell></Row>
<Row><Cell>ui_open_stash_crime_searched</Cell><Cell>Rob</Cell><Cell>Stehlen (durchsucht)</Cell></Row>
<Row><Cell>ui_hud_loot</Cell><Cell>Loot</Cell><Cell>Plündern (durchsucht)</Cell></Row>
</Table>