So...
if the element is active in your task bar...
ctrl key will hold the object in place without placing it
ctrl key + arrow keys or pgup / dn will turn the element in different directions, depending on the set angle (standard: 15 degree)
shift key + arrow keys or pgup / dn will extend or shrink the element in the given direction
arrow keys or pgup / dn will move the element so you can maneuver it into the place you desire
in general you can do a lot of settings by holding the C button. A radial menu will pop up allowing you to do several settings.
i.e. the angle your elements will turn
the positioning precision your elements will move when you maneuver them
the precision in what steps you can extend or shrink the element
save some presets that you use more common than others
also important is that:
- with the return / enter key you can activate or deactivate the modular placing. means that any element will automatically dock onto an already set element that you are aiming at. like a magnet
- pivot points - each element has several pivot points, which make it easier (a lot easier) to build round structures. aim at such a point, use CTRL to hold the element in place and use i.e. ctrl + arrow key to rotate the element. it will rotate around the axis of the pivot point you were aiming at
- with the G key you activate the grid. +/- can make it smaller or larger. the grid is a set "net" of lines on any surface in the world. it allows you to allign walls, etc. in great precision because it eliminates the freedom of placing and hence making it easier to build in straight lines.
collission on/off - i think, but not entirely sure. i never tried that one.
i hope that helps you for a quick start - have fun