Dynamically create chapters based on slidelabels

Using your getSlides array from the code you provides...you can easily get each of the slide lables by using the following code: cp.D[getSlides[n]].lb  Where n is the number of the slide id number in your getSlides array. So if you had written the line as cp.D[getSlides[0]].lb it would give you the slide lable for your very first slide!

Example:

var getSlides = cp.model.data.project_main.slides.split(",");  // getSlides array data [ "Slide13732", "Slide15046", "Slide15902" ]

var slideOneLabel = cp.D[getSlides[0]].lb  // slideOneLabel in my case would hold the value of  "Title Slide"

var slideLabelNamesArray = []; // Create an array to store your slide labels in order
var getSlides = cp.model.data.project_main.slides.split(","); // get current project slide object IDs

// This loop will store all of the slide labels in the slideLabelNamesArray
for(var i=0; i < getSlides.length; i++) {
    slideLabelNamesArray[i] = cp.D[getSlides[i]].lb
}

/* View all of the slide labels in your browsers console log
    in the form of a table. When looking at the generated table
    Think of the (index) column as the slide number..where
    0 is slide one, 1 is slide 2, etc... The Values area
    will show each coresponding slide label */

console.table(slideLabelNamesArray);

    That was just a quick and basic example to go with your orginal quesiton and code......