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Each CRED form creates a single post with it's specific values stored.
If you want to submit multiple posts, you need a value for each of those CRED forms, let's say just minimal, the Post title
This is why you can not create multiple posts with one Form out of the box.
The most difficult is to have a feature that allows you to choose dynamically how many Child posts you are going to create.
If you have a limited number it would be very easy, as example with a Bootstrap Collapse Button on the "Create child CRED form" holding page, that holds all Child Forms you want the user to be able to create.
The user can submit the first form and you redirect him to the same page and so on
It could even be without the Bootstrap Collapse, by just redirecting after each submit to the correct "Create Child" page
It requires a page reload though, and the Posts aren't created all in one bunch.
With repeating Fields you could theoretically allow the user to add as many items of a certain field as he wants and then get this information to create Posts with the API, as example you have a Repeating Single Line Field and use the data to create (wp_insert_post) with each of the values.
the problem here is, the repeating field would be repeatable for each Field, not for each "post".
That means, your user chooses as example 2 "Titles", and then he goes on and chooses 2 Images, etc.
But it would not be a "good user experience", as the suer must think of both (or even more) posts simultaneously and not one after the other.
Also, some Custom Fields can't be repeated, such as Post Body or WYSIWYG.
I do not see any good and User Friendly way to add dynamically a certain amount of Posts with one form on the same "form"/page.
If your Posts can be the almost exact same though, I see a way of programmatically add (wp_insert_post) Posts with a red_save_data function.
You would as example set a Custom Field where you determine how many other posts the user wants to create.
You get this value and wp_insert_post for each of the values you already have, adding a "dynamic" extension to each, just like WordPress does when you create many posts with same title/slug
(post-2, post-3) or similar.
You could get the data from the "real", first form and enrich with eventually even values set in additional Fields the suer must set, if he wants more then one post.
I am eager to help, let us talk how "different" your content should be first, if that's OK for you?
Thank you for your patience.