Hi to all....!!!  I want to apologize for my English, use to write a translating program. 
The title makes reference to two things that I want to ask, and if some of you knows the solution. 
The first one is that when I want to place a floor to some of my alone scenes I obtain a black rectangle without texture, even after making the render. 
The second are referred to the form of as putting a texture to any object, since DazStudio doesn't have rooms like for example Poser that allows us to place materials and textures without inconvenience. 
I want to clarify that the floors without texture are the following products of Daz: "The Studio" The Ballroom", this never happened me in versions previous of DazStudio. 
Thank you for what you can contribute me...!!!  #:O) 
Rodolfo

A black floor probably means you don't have any light shining on it - most likely your lights are close to level, shining into the scene, and that doesn't catch the floor (or other level surfaces).

To change surface settings and load textures you need the Surfaces palette - View>Tabs>Surfaces Click the arrow button next to a colour bar or a strength setting to load or apply an image.

Thank you RHaseltine for the help....!!!  #:O) 
Rodolfo

In Daz select the surfaces Tab on the left.
Then select Tools at the top and select Surface Selection.
You can now select a surface and apply a texture to it.

Under Advanced You will see Diffuse / Color, Select Little black
triangle go to Browse    and select the Texture you want
.You my need to create a bump map for transparencies
One thing you could do is load different objects and see how its put together
Like Hair and check the different surfaces and see what’s making it Look
the way it does. Once you see it its not to hard to figure out.
If You look at Color bar and there is a name under it click on the name and
select Browse that will take you to the folder that texture is in.
If the color bar just has a black triangle click on the triangle and browse
to a texture or materials folder and select the tex you want. Play with
the adjustments until you get it the way you want.
Good Luck and happy rendering