Nuk - lets say you make a box by making a square and pushpulling it vertically. Once you 've done that select it all and right click make group.
You can then moveit, rotate it etc. If you want to change it you double click it and you can alter it.
For studs etc there is a Ruby Pluggin called Housebuilder. One of the neat aspects of sketchup is the ruby scripts others have written for it.
Go to the sketchup forum
http://forum.sketchup.com/
and download housebuilder
http://forum.sketchup.com/showthread.ph ... builder.rb
and install it into you plugins folder in the sketchup root directory. Then reboot sketchup and it will appear as a set of icons.
In house builder you can stipulate the wall height, stud size etc. When you click on the make wall icon you can then draw where the wall goes and bingo - a stud wall is made. You can then select door maker, state the height etc and it will automatically insert a doorway with a top plate etc. similarly with inserting a window.
There are various other ruby scripts and they are adding new ones all the time.
cheers
john