Welcome to the forums, you can use the edit button to add anything you missed like that 'and i havent seen a tutorial anywhere else' part.
As for rounded objects: You use the block tool to create solids right...Well on the right side you will see the word 'block'. You can change that to cylinder to make rounded objects. As for rounded tunnels you can use the 'arch' selection to make a rounded tunnel but it requires some thought and skill.
Feel free to ask more questions.
Edithttp://twhl.co.za/tutorial.php?id=18 - This might be an interesting read.