A Few Questions :D

Well, My Game Is A Survival Game (Stranded On A Island)

It's One Big Map So There Is Only Like 2 Levels.

I Have A Few Questions. 1. How Do I Make It So It Saves (I want it also so on the main menu i can put a load game and it takes you to like 3 games that you can loads, and if you save the game in game it asks what one you want to save it on :D 2. How can i make it change from day and night without making a new scene... 3. How amazing would the person that answers all these right be??

PLEASE MAKE SURE YOU TELL MEH THE SCRIPTZ!!!! (i dont know too much about them, so dont expect me too make them myself!!)

Both questions don't have one-liners as answers. For load/save you could try to adapt the Save and Load scripts from unifycommunity, it will need some understanding of scripting as there isn't a general works for everybody solution.

For day/night, you'll need some scripting skills as well, as you need to have a reference to all scene materials, the lightsources and skybox. Have a script replace the textures of the materials with the night/day version and change position, intensity and colour of light sources and ambient light, and of course put in a different skybox.

UniSky in the Asset Store looks like it could be nice for your day/night needs

In addition to Jaap's helpful response, try searching answers.unity3d.com for "day and night" to see a few other answers.

Saving the game is a common question; search for "save game" to see some of those answers.