In a few weeks this will be possible very easily using the upcoming nestable forms. Until then, you need to create a function that returns each options as documented here → Pro Forms – Bricksforge Docs
Here is an example where I used it to get all the posts of a cpt, just ignore the second snippet about the images n stuff → Images in radio / checkboxes - #2 by manc
I’ve never used ACPT but basically just get your repeater field in a function and then output them into an array of values and labels as shown in the docs and the example. Hope that helps 