What do i do with these textures :)

Heya guys just messing with what i can do before i move into big modeling tasks and i have a few questions regarding the texturing process. Heres what ive done so far

• Created a box and imported it into mudbox
• Created normal & diffuse maps and exported them into photoshop
• Saved each to a separate dds file

I went through a few tutorials on how to link the files to the model in XSI (great tutorials btw guys, thanks so much! :D) but im not entirely clear on what i need to do to these files before they are ready for that stage - and im also missing the specular map!

I saw info on the channels of the images or something along those lines?
Not sure what to do really, any help and guidance is reatly appreciated