Elementor Template Injector

Once you placed the widget, you get the elementor edit panel with it's different tabs:

Content tab
In the content tab you first select the source template: That is the element you want to place at the target selector element. Once this is selected you will see it at the position of the Elementor Template Injector widget. That way you can check if loading the template works. To later only show it in the targeted position, you can enable "Hide Fallback". The second step is to set the target selector. Just use your browsers inspector to find the selector you need and add it to our Target Selector field. And last on the content field there is the option to make sure the injection also works when the target selector is actually on a popup within that page.

Style tab
On the style tab you define the settings of your source template container. Because your template is wrapped into a container and then placed at your target selector. Here you can use most of the container settings you normaly find in the Layout tab of a container widget. Only the Position setting is special, as it defines if the template container should be injected before or after it's targeted element. On top of that we even added options for the parent container of your targeted element. But beware! Enabling and modifying these settings can mess things up. Because you don't know how the parent div is set up CSS wise just from the Elementor editor view. But for those who know what they are doing, this might be a short-cut to better implement your template, compared to otherwise using extra tools like CSS Editors or custom code.