Create a own module

As the first step, we need to introduce a custom module.

Please refer to Create a New Module in Magento’s developer documentation.

In this example, we name the module MyModule_CustomCatalogImport.

mkdir -p app/code/MyModule/CustomCatalogImport/etc
touch app/code/MyModule/CustomCatalogImport/etc/module.xml
touch app/code/MyModule/CustomCatalogImport/registration.php
Content of registration.php
<?php
\Magento\Framework\Component\ComponentRegistrar::register(
    \Magento\Framework\Component\ComponentRegistrar::MODULE,
    'MyModule_CustomCatalogImport',
    __DIR__
);
Content of module.xml
<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
    <module name="MyModule_CustomCatalogImport" setup_version="1.0.0">
        <sequence>
            <module name="TechDivision_PacemakerImportCatalog"/>
        </sequence>
    </module>
</config>

We need to specify TechDivision_PacemakerImportCatalog module in the sequence of our new module.xml to be able to overwrite the existing pipeline configuration.