Backend Module for Magento 1.9.x - magento-1.9

Question

i want to build a new module for Magento 1.9.4 that will be shown in the Admin area (catalog).
I programmed the following code, but i dont know how to show this module in the backend (including form tags). I just get a 404 error.
Here is my code with which i started my first module:
config.xml
<?xml version="1.0"?>
<config>
<modules>
<Eron_ChangePricesPerCategory>
<version>0.1.0</version>
</Eron_ChangePricesPerCategory>
</modules>
<frontend>
<routers>
<changepricespercategory>
<use>standard</use>
<args>
<module>Eron_ChangePricesPerCategory</module>
<frontName>changepricespercategory</frontName>
</args>
</changepricespercategory>
</routers>
</frontend>
<admin>
<routers>
<changepricespercategory>
<use>admin</use>
<args>
<module>Eron_ChangePricesPerCategory</module>
<frontName>admin_changepricespercategory</frontName>
</args>
</changepricespercategory>
</routers>
</admin>
<global>
<helpers>
<changepricespercategory>
<class>Eron_ChangePricesPerCategory_Helper</class>
</changepricespercategory>
</helpers>
</global>
<adminhtml>
<layout>
<updates>
<eron_changepricespercategory>
<file>eron_changepricespercategory.xml</file>
</eron_changepricespercategory>
</updates>
</layout>
</adminhtml>
</config>
adminhtml.xml
<?xml version="1.0"?>
<config>
<acl>
<resources>
<admin>
<children>
<system>
<children>
<config>
<children>
<changepricespercategory_settings translate="title">
<title>Extra Fee Settings</title>
<sort_order>55</sort_order>
</changepricespercategory_settings>
</children>
</config>
</children>
</system>
</children>
</admin>
</resources>
</acl>
</config>
system.xml
<?xml version="1.0"?>
<config>
<sections>
<changepricespercategory translate="label" module="changepricespercategory">
<label>Artikelpreise pro Kategorie ändern</label>
<tab>catalog</tab>
<frontend_type>text</frontend_type>
<sort_order>999</sort_order>
<show_in_default>1</show_in_default>
<show_in_website>1</show_in_website>
<show_in_store>1</show_in_store>
<fields>
<active translate="label">
<label>Aktiviert</label>
<frontend_type>select</frontend_type>
<source_model>adminhtml/system_config_source_yesno</source_model>
<sort_order>10</sort_order>
<show_in_default>1</show_in_default>
<show_in_website>1</show_in_website>
<show_in_store>1</show_in_store>
</active>
<title translate="label">
<label>Title</label>
<frontend_type>text</frontend_type>
<sort_order>20</sort_order>
<show_in_default>1</show_in_default>
<show_in_website>1</show_in_website>
<show_in_store>1</show_in_store>
</title>
<name translate="label">
<label>Name</label>
<frontend_type>text</frontend_type>
<sort_order>30</sort_order>
<show_in_default>1</show_in_default>
<show_in_website>1</show_in_website>
<show_in_store>1</show_in_store>
</name>
<showmethod translate="label">
<label>Versandart zeigen, auch wenn nicht möglich</label>
<frontend_type>select</frontend_type>
<sort_order>50</sort_order>
<source_model>adminhtml/system_config_source_yesno</source_model>
<show_in_default>1</show_in_default>
<show_in_website>1</show_in_website>
<show_in_store>1</show_in_store>
</showmethod>
<specificerrmsg translate="label">
<label>Angezeigte Fehlermeldung</label>
<frontend_type>textarea</frontend_type>
<sort_order>60</sort_order>
<show_in_default>1</show_in_default>
<show_in_website>1</show_in_website>
<show_in_store>1</show_in_store>
</specificerrmsg>
<sort_order translate="label">
<label>Reihenfolge</label>
<frontend_type>text</frontend_type>
<sort_order>70</sort_order>
<show_in_default>1</show_in_default>
<show_in_website>1</show_in_website>
<show_in_store>1</show_in_store>
</sort_order>
</fields>
</changepricespercategory>
</sections>
</config>
IndexController.php (in controllers/Adminhtml)
<?php
class Eron_ChangePricesPerCategory_Adminhtml_IndexController extends Mage_Adminhtml_Controller_Action {
/**
* Admin controller index action
*
* #access public
* #return void
*/
public function indexAction() {
$Block = $this->getLayout()->createBlock('changepricespercategory/Adminhtml_changepricespercategory');
$this->loadLayout()
->_addContent($Block)
->renderLayout();
}
}
The Module is shown in the backend... But i when i click on it, I get a 404. Can anybody help me? Maybe there is a good documentation - im new to magento module developement.
More Information: I want to build a module for changing all prices of a category by a percentage (e.g 2% increase).

Answer 1

You can get started from this toturial:
https://bsscommerce.com/confluence/3-simple-steps-to-create-admin-grid-in-magento-1/
If you want to try more features check this one:
https://www.codealist.com/magento-1-9-x-create-an-adminhtml-controller/