Moving the selected clips around on the timeline is as simple as clicking on them with the left mouse button and dragging them around. You can resize clips directly from the timeline. Simply move the mouse cursor to the beginning or end of the clip you want to resize. Now, click and drag with the left mouse button to resize the clip.
Resizing a clip changes its in and out points. If you reselect the clip and look in the clip monitor, you will see that the in and out points on the monitor show the new positions. It is not possible to resize an audio or video clip past their length - if a clip is 30 seconds in length, then you will not be able to resize the clip so that it finishes playing 35 seconds into the clip! -. On the other hand, you can resize text, image or color clips to increase or reduce their length as you want.
When you are resizing and moving clips, there is a handy "snap to" feature, which will snap the edges of clips to other clips and the current seek position. This is useful for quickly lining clips up with each other, but in some cases may not be what you want. You can turn this behaviour on and off using the "Snap to" icons: