How script on roblox

Hello to be able to script you have to learn a few basics they can be found here
http://wiki.roblox.com/index.php/Scripting

You might also want to use LUA
here: http://www.lua.org/

Lua is much simpler than anything else or you can always either watch a vid on youtube etc or search under Models in Roblox

Hope this helped

P.S. Just get a script from free models and then improve it and say it's yours.