How Save Level when Playing and then load (using PlayerPrefs)?
First of all, you’ll need some way to access all the data you need to save.
If you create a GameData class and put every variable inside this one, it might be a little easier to use.
Secondly you need to program 2 functions, as you mention, a LoadGame() and a SaveGame()
These two functions will then either:
Grab data from PlayerPrefs and store it inside the GameData variables.
or
Grab data from the GameData variables and store them in PlayerPrefs.
PlayerPrefs
http://unity3d.com/support/documentation/ScriptReference/PlayerPrefs.html
You have to use these functions to GET or SET the values from your code.
Whats in your GameData class, I dont know as you havent shown us any code.
(note: I find your question rather general and with too little details, but I have tried to provide something usefull anyhow)
What is PlayerPrefs.Save