1. load the photos into Photoshop and put them in one file, each photo on its own layer. (The order you use is important; each new layer should be the next step in focus depth. If you mix them up stacking them won't work.)
2. select all layers. All layers are marked blue now.
3. Go to edit menu and choose auto-align layers. In the window that opens, just select ok. The automatic mode. This aligns the layers so any movement in the different shots is corrected.
4. Next is combine the layers into one. choose the edit menu, select auto-blend layers. In the window that appears you choose the blend method Stack Images and also check the Seamless Tones and Colors. Press ok.
5. If you find something to be out, you can correct it by editing the layer mask Photoshop created.