With the Move tool selected, selecting multiple layers (or selecting linked layers) allows them be aligned and distributed using the Align and Distribute icons in the Options bar.
If you have an layer that you want to center within in a document, choose Select > All and, with the Move tool chosen, click the "Align vertical centers" and "Align horizontal centers" icons in the Options bar.
When aligning layers, it’s best to turn on Smart Guides. Use the Move tool to reposition the layers - Smart Guides automatically appear when they are aligned at top, center, bottom, left or right.
To reposition a guide using the Move tool, position the Move tool directly on top of the guide. When the icon changes to a double headed arrow, click and drag to reposition the guide. Drag a guide outside of the image area to quickly delete it. Shift-drag a guide to snap it to the ruler tic marks even is the “snap to” option is turned off (View / Snap To...).
When selecting multiple objects with the Move tool, you have the option to check “Show Transform Controls” (in the Options bar) to have Photoshop display a bounding box around selected objects (content on layers). Not only does this help to show which layers are selected but can also be used to quickly transform an object without having to select the Free Transform command.
Option (Mac) / Alt (Win) -drag a layer in the images area with the Move tool creates a copy of a layer. You can also Option (Mac) / Alt (Win) -drag in the Layers panel to duplicate a layer - select the layer(s) and drag until yo see a heavy black line between the layers and release.
In order to drag-select multiple layers, select the Move tool and check the Auto Select option in the Options bar. Click and drag over objects with the Move tool (in the image area) to select the layers. This method works well if you have multiple objects (layers) and a Background. Otherwise, because you have the Auto Select feature turned on, clicking in the image area will select the first layer that you click on and begin to move it instead of selecting additional objects (layers). Note: because a Background is locked by default, it is impossible to select and therefore skipped by the Auto Select Feature. So, if you have layers that you do not want to auto select, lock them. If you prefer to keep the Auto Select Layer unchecked (off), with the Move tool selected, you can use the keyboard shortcut Command (Mac) / Control (Win) to temporarily turn on the auto select functionality.