transform one vector to another.

I know this question has been asked before but I can’t seem to find a answer that satisfies me for some reason. I have a model, and I have two vectors (up and direction) that I need to up this model too.
The up and the direction are perpendicural so if I transform the direction vector of the model to the direction I want to point at the up vector should be the same? So how do I map say the <1,0,0> vector to something like <-.872, -.506, .234> (both normalized)?
thanks for the help…

I figured out for myself! Thanks to all the people who were gonna help me! Thank was nice of ya!