If we are talking about Elementor there is a sufficient difference between a template and a theme. Beginners often get confused with that topic, so to understand the difference it is strongly recommended to read this article (https://www.templatemonster.com/blog/install-elementor-wordpress-template/), where we explain what are both of them in details. In a word, Elementor template is a ready-made set of elements, designed in one style, that are available from the special library inside the page builder. Installation of Elementor template is very simple, after just a few clicks the gorgeous design will be completely at your disposal and you can customize it the way that will fit your needs perfectly. This video Elementor tutorial shows the process in details. Following it allows you to finish the Elementor template installation in a blink of an eye.
If you haven't yet installed the Elementor builder (I think you already have, but just in case), go to Plugins – Add new and type "elementor" to the search bar. Push the "Install now" button and after that activate it.
Now the option of editing via Elementor is available for you when you open the new page or post creation section in WordPress dashboard.
Go to the Elementor Marketplace and get yourself a template.
When a template is already yours there are two ways to install it: via WordPress dashboard or using Elementor functionality. To do it from the dashboard go to the Elementor – My Templates and click "Import Templates".
The imported template will appear in a list and you will be able to view and edit it with Elementor.
The second way is to install it directly from the Elementor builder editing dashboard. When you choose to edit a new page with Elementor, the first thing you will see will be the adding panel, you will be asked to add a new section or a template. Hit the "Add template" button.
You can either choose a .json file from the folder of your PC directories or just drag-and-drop it to the marked area (in that case make sure that dashed line turns blue, otherwise downloading process will not start).
After the finish of importing process, the template will appear in a list. All downloaded templates will be available there, no matter if you installed them via WordPress dashboard or Elementor functionality. From that list, you will be able to preview the template, delete and export it for further use. To start editing it – insert it to the page hitting the "Insert" button.
Voila! You have a ready-made page, containing all the necessary elements. You can edit them any way you like and change the content according to your business needs. All the elements are fully customizable and flexible. Have fun dealing with dozens of color, shape and fonts variations!
In the library, you can choose to go downloading available blocks or pages (some of them are free), but since you've already downloaded a template – go to "My Templates" bar.