First you need to add a hook to call your filter
add_filter('acf/load_value/name=YOUR-REPEATER-FIELD-NAME', 'my_acf_load_value', 20, 3);
In the function above you replace ‘field_name_1’ with the name of the first sub field and add the value for that field. You do this for each sub field. If you want to add a second row you add another nested array for that row’s values.
