how can i apply texture to model?

If the model you have on display in your working space is Female Genesis 3 base compatible, than it shouldn't have any problem with using any skin texture made for Female Genesis 3 and all it's sub characters.

The first step is to select your character in the "scene" tab on the right of your scene.

Then, browse through your content library (or smart content librairy, which ever you feel better to use) and go find some G3F characters you already own.

Normaly, under each of their main folder, they should have a "Material" folder. In there, there is the different texture setting for that character, namely, their skins.

Just double click on their skin mat. (Ofthenly call "Full Body Mat") and it should apply all the default skin texture of that character to your new model in your working space.

And there you go.

P.S: Also, since the description of your problem above wasn't really clear, be sure that your "View display setting" in your working space is set on " Texture Shaded " and not on " Smooth Shaded ". Because if it is the case, you'll always...always see anything in your working space in a coat of white-ish texture.