When you initially built a new Campaign, you picked a template as the first step. However, you can change and/or add an additional template to the campaign you are using by selecting a new one and clicking on 'Install Template'.

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You can also import a shared template here by clicking on Import Template.

The code can be found under any campaign's Action column under Campaigns.
Click the three dots & click Share.

Do be aware that when you opt to install a template, you are presented with the option to overwrite the actions in the current campaign or add to those. Overwriting will remove any actions that are pre-existing in your Campaign. Adding will add the additional actions that are contained within the new template that you are installing or importing.
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