Aligning
You can align the selected elements to the right, left, top or bottom. To do that, select the elements you want to align and then click on the appropriate tool button (shown below).

For align left: the selected elements will be aligned with the left most element.
For align right: the selected elements will be aligned with the right most element.
For align top: the selected elements will be aligned with the top most element.
For align bottom: the selected elements will be aligned with the bottom most element.

Align center and align middle are also available from menu Tools->Align