I know most of you will already know this so this is for the ultimate noobs.

First select the 'Pen Tool (P)' from the 'Toolbar'...
Then up on the 'Options Bar' choose the 'Paths' option...
...and with the 'Pen Tool' still selected trace the area that you want to mask (ie. protect), in this case its the entire building...

Another way to get a selection is with the magnetic lasso tool. This tool I do not use at all but to create a tutorial like this. It can come in handy if you have a VERY distinct subject that really stands out from a common color background; hence, a photo like this...

IR (stands for ImageReady) has to be installed on your computer during the typical Photoshop installation. Run it now independently or switch to it from PS (Photoshop) either by clicking on Jump to ImageReady button at the bottom of PS' Toolbox or using [Ctrl+Shift+M] shortcut...

You can still move layers around in the layer order in the palette. Here you can see that I'm moving the oval fill shape to above the text layer, so that it is now hiding the text layer because of the layer order. The layers are still linked and will move together...

The Rounded Rectangle Tool creates rectangular shapes and paths (shape outlines) with rounded corners.
In the Toolbox, select the Rounded Rectangle Tool. Choose on the Options bar drawing mode: to create vector shape layers click Shape layers button...

Blending modes define how layers, fills, strokes, fades and paths blend. Here is a list of blending modes with a description and examples for each one of them.

1. Select the Shape Tool option (Press the letter U on the keyboard). Hold the mouse click and the drop down option reveals six different Shape options.
2. Once you have selected a basic Shape tool, at the very top of Photoshop's menu area, a new 'Options Bar' appears...

Another palette that you should be aware of is the Histogram palette. This palette shows a real-time preview of all kinds of image information and features the Levels readout from which you can choose the different color channels...

Pencil is freehand painting tool. Unlike Brush it can't have soft edges.
In the Toolbox, select the Pencil Tool. Choose brush size and style. Select color. Paint. On the Options bar you can define also blending mode (on animation I choose Hue) and Opacity...