Unlike most 3 applications, Blender's default selection mouse is all done with the right mouse button.
Now you can change this by simply going into your file and user preferences, and then underneath the input section, and I'll tour all of these settings later,
but in the input section you can see that we have a select with option here, which allows you to choose either left or right.
And this will set which mouse button is used for most kind of selection techniques.
Just be aware that this will also change some other fundamental things in Blender as well, where if they were previously on the left mouse button, will now be on the right.
For demonstration purposes, we're going to go ahead and use the default right mouse button, but if you wish to change it, you can switch it over to the left mouse button,
and then simply click save as default to save those as your default settings.
However, leaving it as the right mouse button for now, selecting objects in Blender is as simple as just right clicking on them.
So you can see if I select an object, you'll notice it turns orange, and the transform manipulator is then centered on that object's origin.
So selecting any one of these objects is no problem.
If you want to select multiple objects, simply hold down the shift key and use your select mouse button, whether that's left or right.
In my case, it's the right mouse button.
So hold down shift and right click on the next object, and you'll add that to your current selection.
If you wish to remove one of these objects from your selection, you must first make it the primary selection,
where you'll notice that the first two objects I selected are kind of a darker orange now,
and the lamp, which was the last one I selected, is a brighter orange.
This means that it's a primary selection and secondary selection.
So if I want to remove, say, the camera from my selection, I would first hold down shift and right click on it,
and you'll notice it becomes my primary selection, and then I can right click on it again while still holding down shift,
and it will remove that from the selection as indicated here.
Next, if we want to select items from the outliner, which again is our hierarchical view of all of the objects within our scene,
it's simply a matter of left clicking on them, no matter which selection mouse you're using, just left click,
since it's within a menu system of sorts.
Left clicking on that object will select it.
If you right click on an object, you'll bring up a select menu that allows you to select, deselect, delete, or other options here.
To deselect, just use the deselect option.
If you hold down shift, you can select multiple objects by just shift left clicking on them.
Or if you want to use, if you have many objects in here, just assuming for a moment that this complete list is filled,
we can actually use border selection by pressing B, and that will bring up this border selection,
that allows me to just left click and drag across these to then select all of those objects.
However, let's look at some more of the selection options within the 3D viewport.
First of all, if you want to toggle everything either selected or unselected, it's simply a matter of pressing the A key.
And the A key will, if you have anything selected, will deselect those objects and anything else,
or if you have nothing currently selected, it will select everything within your current scene, within your current layer.
Now layers and such, we'll look at a little bit more later.
So again, I can select everything with A or deselect with A again.
Now, a couple of different selection options, aside from just the right click, is to use either a paint, lasso, or border selection in the 3D viewport.
First of all, with the lasso selection.
So the lasso selection is just done by holding down control and left click and drag, and again it's just left click and dragging.
Although I believe if you switch to the right mouse button as your main default, it will now be right click and drag.
Minor inconsistency, but that's all right, just keep that in mind.
And the lasso selection allows you to draw out complex selections, simply by holding down control, left click and drag,
and just drawing around the objects that you wish to select.
If you wish to deselect with this, simply hold down control and shift, and you can deselect any of the objects that you wish.
Next we have our border select.
The border select is the same thing that I demoed here, by pressing B, and allows us just to press B,
which point will go into border select mode, and then you can just left click and drag across these objects, and you'll select them.
If you wish to deselect with them, simply hit B, and use your middle click and drag to draw across those.
If you go into border select mode and decide that you don't wish to select anything, simply hit either escape, or your right mouse button to cancel.
For most transforms in Blender, either escape or the right mouse button is cancel, and then left click or enter is confirm.
Lastly, the circle or paint select tool can be accessed by pressing the C key, C for circle, and gives you a circle, which you can then adjust the size by using your scroll wheel up and down,
or the plus and minus keys on your number pad.
And with these, you can simply just left click and paint across any object that you wish, or middle click and paint, or middle click and drag, excuse me, and you can deselect any item you wish.