This is a very easy task if you know how to work with Lightning page layouts. Open the page editor by clicking on the Edit Page link:
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Then drag the CampaignItemRelatedList Custom Component to where you like to position it. In this example we have added it to be a tab called: Campaign Item List. But you can position it anywhere else on your page.
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Click on save an and return to your page. Configure your 8.5.4 Settings for the Custom Campaign Item Related List here.
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