I have problem in scripting the game,in which you can create your stuff.What should I do?

Is is possible to make a game in which whatever u created in ur plot gets saved and next time when u open,u see ur plot is there and ur items too? And if it is,Can you give me directions like what to do or tutorials suggestions or events which will help...

Yes you can, see games like sandbox. It seems like you are new to coding, try looking at the scripting book on roblox wiki, start from there and build up your knowledge http://wiki.roblox.com/index.php?title=Scripting_Book/Contents