Guides are a super useful feature for Adobe Photoshop. You can use them to align / placing all kinds as well as the creation of many unique designs. To show the them, use the view menu and show and select that option. Go to the show command and you can select the them to be on or off. You can also use the view menu to clear them as well as lock them (so avoid moving them by accident).
Select a shape layer and then go to the view menu and new guides from shape command. You can also use vector rectangles as well as ellipses and stars and lines etc. It does not work with the path or pixel option.
You can also use the pen tool to create vector paths that can be used with this feature along with the powerful curvature tool
You can use the feature with a single item as well as multiple items. They will be created will be based on the dimensions of the selected vectors.
If you have an irregular looking vector such as a kettle then the guide will be drawn based on the left, right, top and bottom coordinates. If you have added a stroke to the vector then the stroke is also used for the dimensions so if you set a huge stroke, the result will be lines touching a long way from the original design.
A rectangle is just as easy and you can use the alt / option to duplicate the rectangle and rapidly build up any number of lines using those as you can repeat the command.
You can also move the vector object so yet more additional alignment options are available with the simple act of moving the art.
You can also use type as well