Press M to get to the material editor, then click on an empty sphere slot. After that look a bit down en find the word: Diffuse. Behind this, click on the button, and you see a new screen. Double click on bitmap, find your texture, open it, en then drag the globe you edited to the object you want to texture with it.
After that click in the material editor window on the small cube icon with black and white squares on it, this will show the texture in die viewports.
