How to take good LandScape Shots with me Nikon D5100?

I have just bought a Nikon D5100 and how dose the landscape scene work? It seems to take two photos at one and it turns into a sort of 3D image? It is frustrating me!

Perhaps you should read the manual. Knowing Nikon it's explained in there.

Most of us ditch the scene modes and shoot landscape in A mode.

Once you learn more about photography you'll ignore those silly "Scene Modes" and know how to use your camera in Aperture Priority or Shutter Priority or Manual.

Begin by seriously READING & STUDYING the Owner's Manual for your camera. Spend most of your time reading and re-reading the sections on Aperture Priority and Shutter Priority. Then spend time viewing this video: http://www.nikondigitutor.com/eng/d5100/index.html Who better to teach you to use your Nikon D5100 than Nikon?

I shoot all my landscapes in Aperture Priority with my camera mounted on my tripod. In fact, I consider a tripod as mandatory for good landscapes and can't imagine trying to photograph a landscape without a tripod. I use Aperture Priority because I want control over my Depth of Field (DOF). There are only 3 factors that affect your DOF:
1) The focal length of the lens.
2) The f-stop (aka Aperture) used.
3) The subject distance.

If you aren't familiar with DOF these sites will help you:

http://www.dofmaster.com/dofjs.html This site is more technical and has a DOF Calculator you can use to compute DOF for any combination of the 3 factors imaginable.

http://www.kamerasimulator.se/eng/?page_id=2 This site is more interactive and allows you to easily see how changing 1 of the 3 factors affects your DOF.

A lot of people are under the (mistaken) impression that if you use the 18mm end of your 18-55mm zoom at f16 and focused to infinity you'll maximize your DOF. That is wrong. By using the DOF Calculator and choosing your camera from the list you'll find that if you focus on a subject at 5'-0'' with your lens at 18mm and f16 your DOF will be from 2'-0'' to infinity. Anything from 3'-0'' in front of your subject (2'-0'' in front of your camera) to as far as you can see behind your subject - infinity - will be in focus. If, instead, you choose to focus on a subject at 30'-0'' your DOF will be from 3'-0'' to infinity. Anything from 27'-0'' in front of your subject (3'-0'' in front of your camera) to as far as you can see behind your subject - infinity - will be in focus. So by using a subject at 5'-0'' as your focusing point you can be 1'-0'' closer to an interesting object in the foreground (flowers, a gnarled tree trunk, moss covered rocks - whatever you find interesting) than if you focused on a subject at 30'-0''.

So learn to shoot in Aperture Priority, buy a good tripod, learn about DOF and begin enjoying making the landscape pictures you want to make. A circular polarizer is also recommended. You can use the camera's self-timer to release the shutter.

Both examples are from 35mm film prints scanned and posted to my Flickr account. Absolutely nothing was done to them in the way of editing.

Use manual or aperture priority mode

Go wide with the focal length (18mm), go small with the aperture (f/11-f/16), set the ISO to 100 or 200 and use a tripod. Manually focus 1/3rd of the way into the scene. Shoot.

Set to A mode, f/16, lowest ISO with AF on and WB to Auto. Zoom out (to widest angle, lowest focal length, least mm). If too bright, you can set f/number higher. If cloudy set f/number lower.

Landscape mode taking two photos then making it 3D? Might it be HDR mode instead? Check the manual.