The CSS is split into sections by comments, one for each shape. Simply copy the CSS for the shape you wish to use from the comment down, for example for the heart shape, copy the following CSS:

/*Heart*/

.ds-advent-22-heart .et_pb_image_wrap {
    z-index: 2;
    position: relative;
}

.ds-advent-22-heart .et_pb_main_blurb_image:before,
.ds-advent-22-heart .et_pb_main_blurb_image:after {
    position: absolute;
    content: "";
    top: 10px;
    width: 50px;
    height: 80px;
    background: #ff9047;
    border-radius: 50px 50px 0 0;
    -webkit-transform: rotate(-45deg);
    transform: rotate(-45deg);
    -webkit-transform-origin: 0 100%;
    transform-origin: 0 100%;
}

.ds-advent-22-heart .et_pb_main_blurb_image:before {
    left: 50%;
}

.ds-advent-22-heart .et_pb_main_blurb_image:after {
    right: 50%;
    -webkit-transform: rotate(45deg);
    transform: rotate(45deg);
    -webkit-transform-origin: 100% 100%;
    transform-origin: 100% 100%;
}

Your blurb must have the corresponding class added to the module CSS Class field in the advanced tab:

The blurbs icon shape colours can be changed by searching for the hex code #ff9047 ad replacing it with the colour of your choice.