Click and drag to move an item
Hover over a text box/side panel or image/media and when you see the cross symbol, click and drag the item to its new position (if you are moving a text box/side panel, it's best to click on an area where you will not click on other items within it, such as the top left-hand corner).
Additional options for a text box/side panel
You can also move the text boxes around within the panel by hovering over one of them until you see a cross symbol, then click and drag the box to its new position.
Move items in 1 pixel increments
This gives greater control over the position of an item on the page. To do this, click the item (panel or image) you want to move and hold down the control key on your keyboard. Then use the arrow keys on your keyboard to move the object up and down or left and right.
If you are not holding down the control key, the object will move in 5 pixel increments which makes it easy to line up multiple objects.
Don't forget to click the Save button near the top of the screen after making changes to your page or these will be lost when you navigate away from the page editor screen you're currently in.