How do I make two layers appear or become as one so that blending options can be applied in a seamless manner?

Here's the two images I am working with
1) Tab


2) Folder


First, I don't know how to combine the layers to form as one so that blending options can be applied without separation. As it is now, when I merge them and apply blending options it applies the options for both layers even though they are merged.

Secondly, the tab will used be for navigation and will only be shown when the page is active. I assume I use ImageReady to make the tab visible? For example, if you can picture this:

HOME(tab background) ABOUT(no bg) CONTACT(no bg) etc...

How do I do this?

Thank you for your help
-Capt