Install the Product Relations feature

<?php

namespace Pyz\Zed\Publisher;

use Spryker\Zed\GlossaryStorage\Communication\Plugin\Publisher\GlossaryKey\GlossaryDeletePublisherPlugin as GlossaryKeyDeletePublisherPlugin;
use Spryker\Zed\GlossaryStorage\Communication\Plugin\Publisher\GlossaryKey\GlossaryWritePublisherPlugin as GlossaryKeyWriterPublisherPlugin;
use Spryker\Zed\GlossaryStorage\Communication\Plugin\Publisher\GlossaryPublisherTriggerPlugin;
use Spryker\Zed\GlossaryStorage\Communication\Plugin\Publisher\GlossaryTranslation\GlossaryWritePublisherPlugin as GlossaryTranslationWritePublisherPlugin;
use Spryker\Zed\ProductRelationStorage\Communication\Plugin\Publisher\ProductRelation\ProductRelationWriteForPublishingPublisherPlugin;
use Spryker\Zed\ProductRelationStorage\Communication\Plugin\Publisher\ProductRelation\ProductRelationWritePublisherPlugin;
use Spryker\Zed\ProductRelationStorage\Communication\Plugin\Publisher\ProductRelationProductAbstract\ProductRelationProductAbstractWritePublisherPlugin;
use Spryker\Zed\ProductRelationStorage\Communication\Plugin\Publisher\ProductRelationPublisherTriggerPlugin;
use Spryker\Zed\ProductRelationStorage\Communication\Plugin\Publisher\ProductRelationStore\ProductRelationStoreWritePublisherPlugin;
use Spryker\Zed\Publisher\PublisherDependencyProvider as SprykerPublisherDependencyProvider;

class PublisherDependencyProvider extends SprykerPublisherDependencyProvider
{
    /**
     * @return \Spryker\Zed\PublisherExtension\Dependency\Plugin\PublisherPluginInterface[]
     */
    protected function getPublisherPlugins(): array
    {
        return array_merge(
            ...
            $this->getProductRelationStoragePlugins()
        );
    }

    /**
     * @return \Spryker\Zed\PublisherExtension\Dependency\Plugin\PublisherTriggerPluginInterface[]
     */
    protected function getPublisherTriggerPlugins(): array
    {
        return [
            ...
            new ProductRelationPublisherTriggerPlugin(),
        ];
    }

    /**
     * @return \Spryker\Zed\PublisherExtension\Dependency\Plugin\PublisherPluginInterface[]
     */
    protected function getProductRelationStoragePlugins(): array
    {
        return [
            new ProductRelationWritePublisherPlugin(),
            new ProductRelationWriteForPublishingPublisherPlugin(),
            new ProductRelationProductAbstractWritePublisherPlugin(),
            new ProductRelationStoreWritePublisherPlugin(),
        ];
    }
}

<?php

namespace Pyz\Zed\ProductRelationStorage;

use Pyz\Zed\Synchronization\SynchronizationConfig;
use Spryker\Zed\ProductRelationStorage\ProductRelationStorageConfig as SprykerProductRelationStorageConfig;

class ProductRelationStorageConfig extends SprykerProductRelationStorageConfig
{
    /**
     * @return string|null
     */
    public function getProductAbstractRelationSynchronizationPoolName(): ?string
    {
        return SynchronizationConfig::DEFAULT_SYNCHRONIZATION_POOL_NAME;
    }
}

<?php

namespace Pyz\Zed\Synchronization;

use Spryker\Zed\ProductGroupStorage\Communication\Plugin\Synchronization\ProductGroupSynchronizationDataPlugin;
use Spryker\Zed\Synchronization\SynchronizationDependencyProvider as SprykerSynchronizationDependencyProvider;

class SynchronizationDependencyProvider extends SprykerSynchronizationDependencyProvider
{
    /**
     * @return \Spryker\Zed\SynchronizationExtension\Dependency\Plugin\SynchronizationDataPluginInterface[]
     */
    protected function getSynchronizationDataPlugins(): array
    {
        return [
            new ProductRelationSynchronizationDataRepositoryPlugin(),
        ];
    }
}

<?php

namespace Pyz\Zed\DataImport;

use Spryker\Zed\DataImport\DataImportDependencyProvider as SprykerDataImportDependencyProvider;
use Spryker\Zed\ProductRelationDataImport\Communication\Plugin\ProductRelationDataImportPlugin;
use Spryker\Zed\ProductRelationDataImport\Communication\Plugin\ProductRelationStoreDataImportPlugin;

class DataImportDependencyProvider extends SprykerDataImportDependencyProvider
{
    /**
     * @return array
     */
    protected function getDataImporterPlugins(): array
    {
        return [
            new ProductRelationDataImportPlugin(),
            new ProductRelationStoreDataImportPlugin(),
        ];
    }
}

<?php

namespace Pyz\Zed\Console;

use Spryker\Zed\Kernel\Container;
use Spryker\Zed\Console\ConsoleDependencyProvider as SprykerConsoleDependencyProvider;
use Spryker\Zed\DataImport\Communication\Console\DataImportConsole;
use Spryker\Zed\ProductRelationDataImport\ProductRelationDataImportConfig;

class ConsoleDependencyProvider extends SprykerConsoleDependencyProvider
{
    /**
     * @param \Spryker\Zed\Kernel\Container $container
     *
     * @return \Symfony\Component\Console\Command\Command[]
     */
    protected function getConsoleCommands(Container $container)
    {
        $commands = [
			new DataImportConsole(DataImportConsole::DEFAULT_NAME . ':' . ProductRelationDataImportConfig::IMPORT_TYPE_PRODUCT_RELATION),
            new DataImportConsole(DataImportConsole::DEFAULT_NAME . ':' . ProductRelationDataImportConfig::IMPORT_TYPE_PRODUCT_RELATION_STORE),
		];

		return $commands;
    }
}

<?php

namespace Pyz\Zed\ProductRelationDataImport;

use Generated\Shared\Transfer\DataImporterConfigurationTransfer;
use Spryker\Zed\ProductRelationDataImport\ProductRelationDataImportConfig as SprykerProductRelationDataImportConfig;

class ProductRelationDataImportConfig extends SprykerProductRelationDataImportConfig
{
  	/**
     * @return \Generated\Shared\Transfer\DataImporterConfigurationTransfer
     */
    public function getProductRelationDataImporterConfiguration(): DataImporterConfigurationTransfer
    {
        return $this->buildImporterConfiguration('product_relation.csv', static::IMPORT_TYPE_PRODUCT_RELATION);
    }

    /**
     * @return \Generated\Shared\Transfer\DataImporterConfigurationTransfer
     */
    public function getProductRelationStoreDataImporterConfiguration(): DataImporterConfigurationTransfer
    {
        $moduleDataImportDirectory = $this->getModuleDataImportDirectoryPath();

        return $this->buildImporterConfiguration($moduleDataImportDirectory . 'product_relation_store.csv', static::IMPORT_TYPE_PRODUCT_RELATION_STORE);
    }
}

<?php

namespace Pyz\Zed\ProductRelationGui;

use Spryker\Zed\Kernel\Communication\Form\FormTypeInterface;
use Spryker\Zed\ProductRelationGui\ProductRelationGuiDependencyProvider as SprykerProductRelationGuiDependencyProvider;
use Spryker\Zed\Store\Communication\Plugin\Form\StoreRelationToggleFormTypePlugin;

class ProductRelationGuiDependencyProvider extends SprykerProductRelationGuiDependencyProvider
{
    /**
     * @return \Spryker\Zed\Kernel\Communication\Form\FormTypeInterface
     */
    protected function getStoreRelationFormTypePlugin(): FormTypeInterface
    {
        return new StoreRelationToggleFormTypePlugin();
    }
}