Parallax is an effect where the background content or image in this case, is moved at a different speed than the foreground content while scrolling. Adding it is as easy as using this code in B4J.

Dim parallax1 As ABMParallax
parallax1.Initialize(page, "parallax1", "../images/parallax1.jpg", 500)
page.Cell(1,1).AddComponent(parallax1)

// the other stuff you want to add to the page, like this block

Dim parallax2 As ABMParallax
parallax2.Initialize(page, "parallax2", "../images/parallax2.jpg", 500)
page.Cell(4,1).AddComponent(parallax2)