Making A Sky Dome

To create my sky dome, I started out by creating a 'Geosphere' by clicking on the icon in the right Command Panel, under the Create section. 

I then clicked and dragged in the viewport to create the sphere. Once I'd made my sphere, I clicked in the Modify panel and selected 'Hemisphere'. 

This deleted half of the sphere. 

Now that my hemisphere was made, I needed to add a 'Normal' modifier to it. To do this, I went to the Modifier panel, and from the Modifiers list, I chose 'Normal'. 

I then chose the 'Flip Normals' option in the panel. I did this because it flips the normals of the object so that it is visible from the inside, which is what is needed as my scene is all going to take place within it. 

I now went to the Modifiers list again and this time chose the 'XForm' modifier.

Once the modifier was applied, I went to the 'Gizmo' level within it, and I now wanted to rescale the sphere. I flattened the sphere slightly, by pulling down the vertical axis. I did this because by making the sphere slightly flatter on top, it gives a more realistic feel and shape to it.

Now that I had successfully created my Geosphere, it was now time to add the sky texture I had found previously. To do this, I made sure the sphere was selected, I then went to the Materials Editor window at the top. I selected an empty sphere, then under the Blinn Parameters, I clicked the small grey box next to the Diffuse option. 

I then chose a Bitmap option and selected my Sky texture and applied it to the sphere.