Layout Files

<?xml version="1.0"?>
<!-- file: view/adminhtml/testimonials_testimonialsimport_index.xml -->
<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
    <update handle="testimonials_testimonialsimport_edit"/>
    <body/>
</page>

<?xml version="1.0"?>
<!-- file: view/adminhtml/testimonials_testimonialsimport_edit.xml -->
<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
    <update handle="editor"/>
    <body>
        <referenceContainer name="content">
            <block class="Surething\Testimonials\Block\Adminhtml\Import\Edit" name="testimonials_import_edit"/>
        </referenceContainer>
         <referenceContainer name="left">
            <block class="Surething\Testimonials\Block\Adminhtml\Import\Edit\Tabs" name="testimonials_import_edit_tabs">
                <block class="Surething\Testimonials\Block\Adminhtml\Import\Edit\Tab\ImportInformation" name="testimonials_import_edit_tab_importinformation"/>
                 <action method="addTab">
                    <argument name="name" xsi:type="string">importinformation_section</argument>
                    <argument name="block" xsi:type="string">testimonials_import_edit_tab_importinformation</argument>
                </action>
            </block>
        </referenceContainer>
    </body>
</page>