Unwrap UVW precice size / position

[lucalimonta9]

I'm trying to learn how to use 3Ds Max, so I thought about making Minecraft Steve in 3D because it's a simple model.

I have a problem with Unwrap UVW. How do I move and size each face with precise values? Isn't there a snap like on AutoCAD / Inventor?
I saw that there are coordinates for the position but nothing for the size.

 

Help? Tutorial?
Thank you very much

[lucalimonta9]

This is the texture I want to use. (steve.png)
I tried to download the uvw but it's not accurate. (steve uvw.png)