Lyric Wind

I've been on SL since 2006 but have just started tackling the building aspect, and man is it quite the task. I have a question on something basic. When you rez, say, a cube, you can only stretch it so far. In fact, you can't stretch it all that much at all. I was wondering how I can make it stretch more? Every building I see has bigger floors and walls than how far objects will stretch, do I have to buy something that will allow me to do this, or is it just linking? It really does seem like all one object, which is why I ask. I also remember someone pulling out a huge platform to begin to build with, but I forget what it is and I don't know how to get it. Sorry for the lame question, I appreciate every answer.