Sorry if my reply was “cryptic”.
ACF is built for developers, when I say “developers” I mean people that code in PHP and are able to modify the templates and code in a theme to use the fields. ACF is an admin tool that makes creation of fields in the admin easier for the developer and give the editor a nice UI to use to add content to these fields.
What code to use? Every field is explained in the documentation and has example code for use in your theme.
Where does the code go? This is highly dependent on your theme. For a theme that you build, if you are familiar with how to build a theme then this is most likely self explanatory. The code goes in the theme template where you want the value of a field to be shown. If you are attempting to modify an existing theme then you need to figure out where this is. It may require editing one of the existing theme templates. It might require using action/filter hooks provided by the theme. Again, if you are familiar with building and/or modifying themes then you likely already have some idea of what this means. When using filters to add or modify content then these filters will generally be added to your functions.php file.
As an example let’s look at WooCommerce. WC is a plugin that includes many template files as well has hooks that can be used for showing additional content or modifying content that is displayed. Templates can be overridden by copying template files to your theme. WC also has many hooks that are available to use. If you override a template then you can output ACF fields by modifying those templates. If you are using filter or action hooks then you would add your filters and actions to your functions.php file.
ACF is not generally as useful if you do not have the ability to modify templates and do the PHP coding necessary to use the fields that ACF creates. It is not really meant for those that use “Theme Builders” or “Theme Frameworks” unless you have the ability and understanding of how to add custom code to these things. For those that want to use these tools and not do the coding needed there are other tools available for this purpose, like “Pods” and “Toolset”.
There are simply too many possibilities for ACF to be able to explain how to use fields in every theme, plugin, builder and framework that is available. Getting help here on these things will depend on some other user that participates in this forum knowing how to do so. In most cases you need to talk to the developers of these other things. I you can figure out how to use a standard custom WP field in those other things then you can use ACF by replacing the code used for using those fields with ACF coding. If you can figure out how to use a custom field in these other things then you are more likely to get help here on how to modify that to use ACF fields.
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