How to get images on homepage as in example screenshot

I would like to make my site using your template look similar to your example screenshot. The example homepage has the three widgets labeled “Our Vision”, “Our Services”, and “Our Team”. The only way I could find to get these sections to show in that place on the homepage was to add three Text widgets to the Alt_Homepage Sidebar. However, unlike in your screenshot where the images in those sections go all the way to the edges of the white box containing the text underneath and to just under the widget Text, my images are scaled to fit with a margin on the top and both sides. How can I replicate your example?

Also, I can’t figure out how to get the homepage slider to work. In Appearance -> Customize, you provide the section “Slider Options”, which is described as “Adjust the behavior of the background image slider on Alt_Homepage”. However, I can only get it to show one background image. Under Customize, it is only possible to select one background image. I tried adding them as media to my static page, but it did not work. Where do I put the background images to get the slider to work?