Questin about blending two exposures tutorial

[Jennifer]

Been a long time since I needed to do this. in the article where it says -

"Then I placed them on top of each other in Photoshop …" how do I do that? I processed one and left it as a raw file in photoshop, then I went to bridge and processed the other one. Just forgot how to place the one layer on top of the other.

[Damien Symonds]

Literally just copy and paste.