Changing floor on an image - part 1

Start by opening the picture, select the Pen tool on Tools palete and drawing the borders of the floor that we'll change.

Duplicate the background layer; we have to options for doing this:

The faster option: Hold your left mouse button on the background layer and drag it to the New layer icon on layers palete.

The slower option: Right click on the background layer, select Diplicate layer from the drop down menu, set a name for the new layer and press the Enter key or click on Ok button.

Once we have our duplicated layer, hide the Background layer by clicking on the eye icon located at its left.

Now select the Paths tab, right click on Work path and select make selection from the drop down menu.

On the new window use this settings:

Feather radius - 0 pixels
Anti-aliased: Check this checkbox
Operation: New selection

After doing this, the area we've drawn with the pen tool will be selected.

Now, with the Background copy layer still selected, delete the selection by pressing the Delete key on your keyboard or selecting from menu Edit / clear.

The floor area now should be transparent; here we can verify if we've made fine our selection.