The Rectangle Tool creates rectangular shapes and paths (shape outlines).
In the Toolbox, select the Rectangle Tool.
In the Options bar, choose a drawing mode: to create vector shape layers
click the "Shape layers" button; to draw paths (shape outlines) click the "Paths" button; to create rasterized shapes in current layer click the "Fill pixels" .
In the Options bar, click on next to button to set geometry options.
Choose a color for your shape*.
Drag on the image.
When creating multiple shapes, use selector in the Options bar:
Create new shape layer
- to create every new shape in a separate layer
Add to shape area
- to create mutiple shapes in the same vector shape layer.
Subtract from shape area
- to subtract shapes from the current shape
layer.
Intersect with shape area
- to intersect new shapes with existing one(s) in the same
layer.
Exclude overlapping shape areas
- to create new shapes in the current shape layer subtracting
overlapping areas.
To apply some special effects to created shape layers, choose
a style in Style picker (on the Options
bar).
When creating paths, you can select
add,
subtract,
intersect and
exclude overlapping modes.
Working in Fill pixels mode you can also choose in the Options bar
opacity and blending mode.
*To change color while creating shape layers, first turn off the "linked" gadget in the Options bar.
Tool creates rectangular shapes and paths (shape outlines).
button; to draw paths (shape outlines) click the "Paths" 
button; to create rasterized shapes in current layer click the "Fill pixels" 
.
next to 
button to set geometry options.
selector in the Options bar:
- to create every new shape in a separate layer
- to create mutiple shapes in the same vector shape layer.
- to subtract shapes from the current shape
layer.
- to intersect new shapes with existing one(s) in the same
layer.
- to create new shapes in the current shape layer subtracting
overlapping areas.
gadget in the Options bar.