Hint: Draw your shape from back to front and from bottom to top, to assure proper alignment of cubes.
Also, when adding adjacent cubes, be sure to click on the face of the cube you want to be touching.
As we see, that the above given figure is the oblique sketch
$\Rightarrow$ An Oblique sketch is drawn on paper having a grid.
$\Rightarrow$ So we have to make the isometric sketch of the above figure in isometric dot paper.
As we know that isometric dot paper is a paper filled with dots equally spaced from each other.
$\Rightarrow$ Isometric sketch of the above oblique sketch in isometric paper is drawn above.
NOTE: - Whenever you come up with this type of question then only you have to change the paper. As oblique sketch is drawn in grid paper, the isometric sketch is drawn in isometric dot paper.