The NX help documentation and the "command finder" are great resources to learn the basics about commands (what it does and where to find it). Use the command finder and type in the name of a command (or equivalent name from another CAD system), it will show you where to find the command in the menus/toolbars. After you start the command, you can press [kbd]F1[/kbd] to pull up the help file information.
NX help is a separate install, it is not automatically installed with NX. If you have a valid NX license, you can log into the GTAC website and download the help documentation for your version of NX.
Wave geometry is a copy of another part into your work part, it can be "dumb" or associative which means that if the parent part changes your new part will see those changes. Be careful though as it can make a part heavy extremely quickly. It's handy if you're making a complex beam for instance and you need the top and bottom plates to follow the web.
Extract geometry is an associative copy INSIDE a part. So geometry you've modelled is copied.
and with extract geometry you have a choice between extracting just a face (or number of faces) or the entire solid body.
I use extract body to have two differnt versions of the same part in one file: such as the cast and machined versions of it.
